{"id":4595,"date":"2026-05-30T06:13:10","date_gmt":"2026-05-30T05:13:10","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/"},"modified":"2026-10-25T12:17:06","modified_gmt":"2026-10-25T12:17:06","slug":"seesaw","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/","title":{"rendered":"SeeSaw"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-seesaw-9ch0-page\">\n  <style>\n    .ols-revision-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --soft-blue: #eef4ff;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-green: #f0f7f1;\n      --soft-orange: #fff7ed;\n      --gold: #c9973a;\n      --grey-text: #667085;\n      --body-text: #1f2937;\n      --border: rgba(28, 36, 75, 0.14);\n      --shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      --inner-shadow: 0 10px 26px rgba(28, 36, 75, 0.08);\n      font-family: Poppins, Arial, sans-serif;\n      color: var(--navy);\n      background: #ffffff;\n    }\n\n    .ols-revision-page * { box-sizing: border-box; }\n    .ols-main { min-width: 0; max-width: 970px; }\n    .ols-breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0 22px; font-size: 15px; color: var(--grey-text); }\n    .ols-breadcrumbs a, .ols-breadcrumbs span { color: var(--grey-text); text-decoration: none; font-weight: 600; }\n    .ols-breadcrumbs a:hover { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; }\n    .ols-title-card, .ols-note-card, .ols-h5p-card, .ols-related-card, .ols-faq-card { background: #ffffff; border: 1px solid var(--border); border-radius: 28px; box-shadow: var(--shadow); padding: 34px; margin-bottom: 24px; overflow: hidden; }\n    .ols-title-card { background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%); }\n    .ols-title-card h1 { margin: 0 0 18px; font-size: clamp(36px, 5vw, 58px); line-height: 1.08; font-weight: 800; letter-spacing: -0.04em; color: #111827; }\n    .ols-page-intro { font-size: 19px; line-height: 1.7; font-weight: 300; color: var(--body-text); margin: 0 0 22px; }\n    .ols-badges { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 22px; }\n    .ols-badge { display: inline-flex; align-items: center; padding: 9px 14px; border-radius: 999px; background: #ffffff; border: 1px solid var(--border); font-size: 15px; font-weight: 600; color: var(--navy); }\n    .ols-author { display: flex; align-items: center; gap: 20px; padding: 28px; border-radius: 28px; background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%); border: 1px solid rgba(28,36,75,0.12); box-shadow: 0 18px 45px rgba(28,36,75,0.10); margin-top: 22px; }\n    .ols-author-avatar-img { width: 92px; height: 92px; border-radius: 50%; object-fit: cover; object-position: center; flex-shrink: 0; border: 4px solid #ffffff; box-shadow: 0 14px 32px rgba(28,36,75,0.18), 0 0 0 1px rgba(28,36,75,0.10); transition: transform 0.25s ease, box-shadow 0.25s ease; }\n    .ols-author:hover .ols-author-avatar-img { transform: scale(1.04); box-shadow: 0 20px 42px rgba(28,36,75,0.22), 0 0 0 1px rgba(28,36,75,0.10); }\n    .ols-author-content { min-width: 0; }\n    .ols-author-title { margin: 0 0 4px; font-size: clamp(24px,3vw,34px); line-height: 1.15; font-weight: 700; color: var(--navy); letter-spacing: -0.03em; }\n    .ols-author-description { margin: 0; font-size: 17px; line-height: 1.7; font-weight: 300; color: var(--grey-text); }\n    .ols-linkedin-pill { display: inline-flex; align-items: center; justify-content: center; gap: 10px; margin-top: 16px; padding: 11px 18px; border-radius: 999px; background: linear-gradient(135deg,#0A66C2,#004182); color: #ffffff; text-decoration: none; font-size: 14px; line-height: 1; font-weight: 700; letter-spacing: 0.01em; box-shadow: 0 10px 22px rgba(10,102,194,0.24); position: relative; overflow: hidden; transition: transform 0.22s ease, box-shadow 0.22s ease; }\n    .ols-linkedin-pill::before { content: \"\"; position: absolute; top: 0; left: -120%; width: 100%; height: 100%; background: linear-gradient(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0) 100%); transition: left 0.7s ease; }\n    .ols-linkedin-pill:hover { transform: translateY(-3px) scale(1.03); box-shadow: 0 16px 34px rgba(10,102,194,0.34), 0 0 0 6px rgba(10,102,194,0.10); color: #ffffff; }\n    .ols-linkedin-pill:hover::before { left: 120%; }\n    .ols-linkedin-icon { width: 18px; height: 18px; display: block; flex-shrink: 0; }\n    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%); }\n    .ols-note-card.orange { background: linear-gradient(135deg, #ffffff 0%, var(--soft-orange) 100%); }\n    .ols-note-title { display: flex; align-items: center; gap: 14px; margin-bottom: 20px; }\n    .ols-note-icon { width: 52px; height: 52px; border-radius: 16px; background: var(--navy); color: #ffffff; display: grid; place-items: center; font-size: 24px; font-weight: 800; flex-shrink: 0; }\n    .ols-note-title h2, .ols-h5p-card h2, .ols-related-card h2, .ols-faq-card h2 { margin: 0; font-size: clamp(28px, 3.5vw, 42px); line-height: 1.15; font-weight: 800; color: #111827; letter-spacing: -0.03em; }\n    .ols-h5p-card h2, .ols-related-card h2, .ols-faq-card h2 { margin-bottom: 14px; }\n    .ols-note-card p, .ols-note-card li { font-size: clamp(15px, 1.25vw, 17px); line-height: 1.65; font-weight: 300; color: var(--body-text); }\n    .ols-h5p-card p, .ols-related-card p, .ols-faq-card p { font-size: clamp(15px, 1.3vw, 18px); line-height: 1.65; font-weight: 300; color: var(--body-text); }\n    .ols-note-card strong, .ols-h5p-card strong, .ols-related-card strong, .ols-faq-card strong { font-weight: 700; color: var(--navy); }\n    .ols-note-card ul, .ols-note-card ol { margin: 0; padding-left: 22px; }\n    .ols-key-box { margin-top: 20px; background: var(--soft-green); border: 1px solid rgba(63, 143, 70, 0.25); border-radius: 20px; padding: 18px 20px; }\n    .ols-key-box p { margin: 0; font-weight: 400; color: var(--navy); }\n    .ols-definition-box { background: linear-gradient(135deg, #ffffff, var(--soft-purple)); border: 2px dashed rgba(122, 62, 157, 0.35); border-radius: 24px; padding: 22px 24px; margin-top: 22px; }\n    .ols-definition-box p { margin: 0; color: var(--navy); font-weight: 400; }\n    .ols-rule-list { display: grid; gap: 14px; margin-top: 18px; }\n    .ols-rule-item { background: #ffffff; border: 1px solid var(--border); border-left: 5px solid var(--blue); border-radius: 18px; padding: 18px; box-shadow: var(--inner-shadow); }\n    .ols-rule-item h3 { margin: 0 0 8px; font-size: 20px; line-height: 1.25; color: var(--navy); }\n    .ols-rule-item p { margin: 0; font-size: 15px; line-height: 1.6; }\n    .ols-figure-card { margin: 26px auto 4px; border: 1px solid var(--border); border-radius: 26px; overflow: hidden; background: #ffffff; box-shadow: var(--inner-shadow); max-width: 100%; }\n    .ols-figure-card.medium { max-width: 820px; }\n    .ols-figure-card.compact { max-width: 700px; }\n    .ols-figure-image { width: 100%; min-height: 260px; display: flex; align-items: center; justify-content: center; background: #ffffff; padding: 20px; }\n    .ols-figure-image img { max-width: 100%; height: auto; display: block; }\n    .ols-figure-caption { padding: 18px 24px 22px; background: linear-gradient(135deg, #ffffff, #f8fbff); border-top: 1px solid var(--border); }\n    .ols-figure-caption p { margin: 0; color: #5f6b85; font-size: clamp(15px, 1.3vw, 17px); line-height: 1.6; font-weight: 300; font-style: italic; }\n    .ols-zoom-figure { overflow: visible; position: relative; z-index: 1; }\n    .ols-zoom-figure:hover { z-index: 20; }\n    .ols-lightbox-trigger { border: 0; cursor: zoom-in; width: 100%; }\n    .ols-zoom-figure .ols-figure-image img { transition: transform 0.32s ease, box-shadow 0.32s ease; transform-origin: center center; }\n    .ols-zoom-figure:hover .ols-figure-image img { transform: scale(1.12); box-shadow: 0 24px 60px rgba(28, 36, 75, 0.22); }\n    .ols-image-lightbox { position: fixed; inset: 0; z-index: 99999; display: none; align-items: center; justify-content: center; padding: 24px; background: rgba(10, 16, 34, 0.84); }\n    .ols-image-lightbox.is-open { display: flex; }\n    .ols-image-lightbox img { max-width: min(96vw, 1200px); max-height: 92vh; border-radius: 18px; background: #ffffff; box-shadow: 0 28px 80px rgba(0, 0, 0, 0.35); }\n    .ols-image-lightbox-close { position: fixed; top: 18px; right: 18px; width: 44px; height: 44px; border: 0; border-radius: 999px; background: #ffffff; color: var(--navy); font-size: 26px; line-height: 1; font-weight: 700; cursor: pointer; box-shadow: 0 10px 28px rgba(0, 0, 0, 0.22); }\n    .ols-table-wrap { overflow: hidden; border-radius: 22px; border: 1px solid var(--border); background: #ffffff; margin-top: 18px; }\n    .ols-table { width: 100%; border-collapse: collapse; table-layout: fixed; }\n    .ols-table th { background: var(--navy); color: #ffffff; padding: 16px; text-align: left; font-size: clamp(14px, 1.2vw, 17px); font-weight: 600; overflow-wrap: anywhere; }\n    .ols-table td { padding: 16px; border-bottom: 1px solid var(--border); font-size: clamp(14px, 1.15vw, 16px); line-height: 1.45; color: var(--body-text); vertical-align: top; overflow-wrap: anywhere; }\n    .ols-table tr:last-child td { border-bottom: none; }\n    .ols-h5p-card { background: linear-gradient(135deg, #ffffff 0%, #f7f0ff 100%); }\n    .ols-h5p-frame { margin-top: 22px; padding: 18px; border-radius: 24px; background: #ffffff; border: 1px solid var(--border); box-shadow: inset 0 0 0 1px rgba(28, 36, 75, 0.03); }\n    .ols-faq-list { display: grid; gap: 14px; margin-top: 18px; }\n    .ols-faq-item { background: #ffffff; border: 1px solid var(--border); border-radius: 18px; padding: 18px 20px; box-shadow: var(--inner-shadow); }\n    .ols-faq-item h3 { margin: 0 0 8px; font-size: 20px; line-height: 1.3; color: var(--navy); }\n    .ols-faq-item p { margin: 0; font-size: 16px; line-height: 1.65; color: var(--body-text); }\n    .ols-related-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin-top: 18px; }\n    .ols-related-item { border: 1px solid var(--border); border-radius: 18px; padding: 18px; background: #ffffff; color: var(--navy); text-decoration: none; font-weight: 600; line-height: 1.5; transition: transform 0.2s ease, box-shadow 0.2s ease; }\n    .ols-related-item:hover { transform: translateY(-2px); box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08); }\n    .ols-attribution-card { background: linear-gradient(135deg, #ffffff, #f8fbff); border: 1px solid rgba(28, 36, 75, 0.14); border-radius: 28px; box-shadow: 0 18px 45px rgba(28, 36, 75, 0.10); padding: 34px; margin-bottom: 24px; overflow: hidden; font-family: Poppins, Arial, sans-serif; box-sizing: border-box; }\n    .ols-attribution-card, .ols-attribution-card * { box-sizing: border-box; }\n    .ols-attribution-card p { margin: 0; font-size: 14px; line-height: 1.65; font-weight: 300; color: #667085; }\n    .ols-attribution-card strong { font-weight: 700; color: #1C244B; }\n\n    @media (max-width: 1050px) {\n      .ols-main { max-width: none; }\n      .ols-related-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n    }\n\n    @media (max-width: 760px) {\n      .ols-title-card, .ols-note-card, .ols-h5p-card, .ols-related-card, .ols-faq-card, .ols-attribution-card { padding: 24px 18px; border-radius: 22px; }\n      .ols-note-title { align-items: flex-start; }\n      .ols-related-grid { grid-template-columns: 1fr; }\n      .ols-figure-card { border-radius: 22px; }\n      .ols-figure-image { min-height: 210px; padding: 14px; }\n      .ols-figure-caption { padding: 16px; }\n      .ols-table-wrap { border: none; background: transparent; }\n      .ols-table, .ols-table thead, .ols-table tbody, .ols-table th, .ols-table td, .ols-table tr { display: block; width: 100%; }\n      .ols-table { border-collapse: separate; border-spacing: 0; }\n      .ols-table thead { display: none; }\n      .ols-table tr { margin-bottom: 14px; border: 1px solid var(--border); border-radius: 18px; overflow: hidden; background: #ffffff; box-shadow: var(--inner-shadow); }\n      .ols-table td { border-bottom: 1px solid var(--border); padding: 14px 16px; overflow-wrap: anywhere; }\n      .ols-table td:last-child { border-bottom: none; }\n      .ols-table td::before { content: attr(data-label); display: block; margin-bottom: 6px; font-size: 13px; font-weight: 700; color: var(--blue); }\n      .ols-author { align-items: flex-start; padding: 22px 18px; border-radius: 22px; }\n      .ols-author-avatar-img { width: 72px; height: 72px; }\n      .ols-author-title { font-size: 24px; }\n      .ols-author-description { font-size: 15px; }\n    }\n  \n    .ols-figure-placeholder .ols-placeholder-box { border: 2px dashed #c9973a; background: #fffaf0; border-radius: 16px; padding: 26px 22px; font-weight: 700; color: #7a4b12; text-align: center; line-height: 1.6; }\n    .ols-figure-placeholder .ols-figure-image { background: transparent; }\n    .ols-figure-placeholder { background: #ffffff; border: 1px solid rgba(28, 36, 75, 0.12); border-radius: 22px; padding: 14px; margin: 18px 0 6px; }\n    .ols-figure-placeholder .ols-figure-caption p { margin: 10px 0 0; font-size: 14px; color: #667085; text-align: center; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Topic 2 Bonding and Structure<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/\">Ionic Bonding<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/nature-of-ionic-bonding\/\">Nature of Ionic Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/polarisation-of-ions\/\">Polarisation of Ions<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/physical-properties-of-ionic-compounds\/\">Physical Properties of Ionic Compounds<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/\">Covalent Bonding<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/nature-of-covalent-bonding\/\">Nature of Covalent Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/dative-covalent-bonding\/\">Dative Covalent Bonding<\/a>\r\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/giant-covalent-structures\/\">Giant Covalent Structures<\/a>\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/electronegativity\/\">Electronegativity<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/\">Shapes of Molecules<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/linear\/\">Linear<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/trigonal-planar\/\">Trigonal Planar<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/tetrahedral\/\">Tetrahedral<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/trigonal-pyramidal\/\">Trigonal Pyramidal<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/bent\/\">Bent<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/trigonal-bipyramidal\/\">Trigonal Bipyramidal<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/octahedral\/\">Octahedral<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/square-planar\/\">Square Planar<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/square-pyramidal\/\">Square Pyramidal<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/distorted-t\/\">Distorted T<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/\">SeeSaw<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/polar-molecules\/\">Polar Molecules<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/metallic-bonding\/\">Metallic Bonding<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/metallic-bonding\/metallic-bonding-and-structure\/\">Metallic Bonding and Structure<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/metallic-bonding\/physical-properties-of-metals\/\">Physical Properties of Metals<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/\">Intermolecular Forces<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/london-forces\/\">London Forces<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/permanent-dipole-dipole-forces\/\">Permanent Dipole-Dipole Forces<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/hydrogen-bonding\/\">Hydrogen Bonding<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/anomalous-properties-of-water\/\">Anomalous Properties of Water<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/boiling-temperature-trends\/\">Boiling Temperature Trends<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/intermolecular-forces\/choosing-solvents\/\">Choosing Solvents<\/a>\n          <\/li>\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/structure-types\/\">Structure Types<\/a>\r\n      <\/li>\r\n\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Next Topics<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-3-redox-i\/\">Redox I<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-4-inorganic-chemistry-and-the-periodic-table\/\">Inorganic Chemistry &amp; The Periodic Table<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-5-formulae-equations-and-amounts-of-substance\/\">Formulae, Equations &amp; Amounts<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      .replace(\/\\\/+$\/, '')\r\n      .toLowerCase();\r\n  }\r\n\r\n  function highlightActive() {\r\n    var sidebar = document.querySelector('.ols-sidebar');\r\n    if (!sidebar) return false;\r\n\r\n    var currentPath = normalisePath(window.location.pathname);\r\n    var links = sidebar.querySelectorAll('a[href]');\r\n    var matched = null;\r\n    var matchedLength = 0;\r\n\r\n    sidebar.querySelectorAll('.active, .active-main, .parent-active').forEach(function(item) {\r\n      item.classList.remove('active', 'active-main', 'parent-active');\r\n    });\r\n\r\n    sidebar.querySelectorAll('a[data-ols-disabled-parent=\"1\"], a[aria-current]').forEach(function(a) {\r\n      a.removeAttribute('aria-current');\r\n      a.removeAttribute('tabindex');\r\n      a.removeAttribute('data-ols-disabled-parent');\r\n    });\r\n\r\n    links.forEach(function(a) {\r\n      try {\r\n        var href = a.getAttribute('href');\r\n        if (!href || href === '#' || href.charAt(0) === '#') return;\r\n        var linkPath = normalisePath(new URL(href, window.location.origin).pathname);\r\n        if (!linkPath) return;\r\n        if (currentPath === linkPath || currentPath.indexOf(linkPath + '\/') === 0) {\r\n          if (linkPath.length > matchedLength) {\r\n            matched = a;\r\n            matchedLength = linkPath.length;\r\n          }\r\n        }\r\n      } catch(e) {}\r\n    });\r\n\r\n    if (matched) {\r\n      var matchedLi = matched.closest('li');\r\n      var parentSub = matched.closest('.ols-subtopic-list');\r\n\r\n      if (parentSub) {\r\n        if (matchedLi) {\r\n          matchedLi.classList.add('active');\r\n          matched.setAttribute('aria-current', 'page');\r\n        }\r\n        var parentLi = parentSub.closest('li');\r\n        if (parentLi) {\r\n          parentLi.classList.add('parent-active', 'active-main');\r\n          var parentLink = parentLi.querySelector(':scope > a');\r\n          if (parentLink) {\r\n            parentLink.setAttribute('aria-current', 'true');\r\n            parentLink.setAttribute('tabindex', '-1');\r\n            parentLink.setAttribute('data-ols-disabled-parent', '1');\r\n          }\r\n        }\r\n      } else {\r\n        if (matchedLi) {\r\n          matchedLi.classList.add('parent-active', 'active-main');\r\n          matched.setAttribute('aria-current', 'page');\r\n          matched.setAttribute('tabindex', '-1');\r\n          matched.setAttribute('data-ols-disabled-parent', '1');\r\n        }\r\n      }\r\n    }\r\n\r\n    return true;\r\n  }\r\n\r\n  if (!highlightActive()) {\r\n    document.addEventListener('DOMContentLoaded', highlightActive);\r\n  }\r\n})();\r\n<\/script>\n\n<main class=\"ols-main\">\n      <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\">Edexcel<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/\">Topic 2 Bonding and Structure<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/\">Shapes of Molecules<\/a> \/\n        <span>SeeSaw<\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>SeeSaw Molecular Shape<\/h1>\n        <p class=\"ols-page-intro\">A focused revision guide to the SeeSaw molecular shape, using SF<sub>4<\/sub> as the key example.<\/p>\n<p class=\"ols-page-intro\">This page explains why four bonding pairs and one lone pair around a central atom give a SeeSaw arrangement with bond angles a little smaller than the ideal 120&deg;, 90&deg; and 180&deg;.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Unit: Paper 1<\/div>\n          <div class=\"ols-badge\">Topic 2: Bonding and Structure<\/div>\n          <div class=\"ols-badge\">9CH0\/01<\/div>\n        <\/div>\n      <\/header>\n<!-- 3D card: sf4-seesaw (swapped 26 Sep 2026) -->\n<!-- Copyright (c) 2026 Dr. Mohammed Al-Fatah, onlinelearningsystem.net. All rights reserved. -->\n<!-- 3D card: sf4-seesaw (rebuilt Oct 2026) -->\n<!-- Copyright (c) 2026 Dr. Mohammed Al-Fatah, onlinelearningsystem.net. All rights reserved. -->\n<section class=\"ols-sfss-001\" id=\"olsSfss001\">\n<style>\n@import url('https:\/\/fonts.googleapis.com\/css2?family=Poppins:wght@300;400;500;600&display=swap');\n\n.ols-sfss-001{\n  font-family:'Poppins',system-ui,-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;\n  color:#1C244B; background:#ffffff;\n  border:1px solid rgba(28,36,75,0.14);\n  border-radius:28px;\n  box-shadow:0 18px 45px rgba(28,36,75,0.10);\n  padding:44px; margin:26px auto; max-width:980px;\n  box-sizing:border-box; -webkit-font-smoothing:antialiased;\n}\n.ols-sfss-001 *{box-sizing:border-box;}\n\n.ols-sfss-001 .sfss-head{margin:0 0 22px;}\n.ols-sfss-001 h2.sfss-title{\n  font-size:26px; line-height:1.25; font-weight:600; letter-spacing:-0.012em;\n  margin:0 0 9px; color:#1C244B;\n}\n.ols-sfss-001 p.sfss-sub{\n  font-size:14.5px; line-height:1.62; font-weight:300; color:#4a5270;\n  margin:0; max-width:66ch;\n}\n\n.ols-sfss-001 .sfss-stage{\n  position:relative; width:100%; height:540px;\n  background:#ffffff; border:1px solid rgba(28,36,75,0.12);\n  border-radius:18px; overflow:hidden;\n}\n.ols-sfss-001 .sfss-canvas{\n  display:block; width:100%; height:100%;\n  touch-action:none; cursor:grab; background:#ffffff;\n}\n.ols-sfss-001 .sfss-canvas.is-drag{cursor:grabbing;}\n.ols-sfss-001 .sfss-overlay{position:absolute; inset:0; pointer-events:none; overflow:hidden;}\n\n.ols-sfss-001 .sfss-lab{\n  position:absolute; left:0; top:0; transform:translate(-50%,-50%);\n  white-space:nowrap; font-size:12.5px; font-weight:500; line-height:1;\n  padding:5px 10px; background:rgba(255,255,255,0.93);\n  border:1px solid rgba(28,36,75,0.16); border-radius:999px;\n  color:#1C244B; will-change:transform;\n}\n.ols-sfss-001 .sfss-lab.l-part{font-size:11.5px; color:#3c4463;}\n.ols-sfss-001 .sfss-lab.l-msg{font-weight:600; border-color:rgba(28,36,75,0.32);}\n.ols-sfss-001 .sfss-lab.l-ok{font-weight:600; border-color:rgba(47,158,87,0.8); color:#1f7a3a;}\n.ols-sfss-001 .sfss-lab.l-bad{font-weight:600; border-color:rgba(212,58,50,0.7); color:#b02a24;}\n.ols-sfss-001 .sfss-lab.l-hi{font-weight:600; border-color:rgba(201,150,28,0.75); color:#8a6410;}\n.ols-sfss-001 .sfss-lab.l-blue{font-weight:600; border-color:rgba(70,125,190,0.55); color:#2f5f9a;}\n.ols-sfss-001 .sfss-lab.l-read{font-size:14px; font-weight:600; border-color:rgba(28,36,75,0.45); padding:6px 12px;}\n\n.ols-sfss-001 .sfss-caption .c-ok{color:#1f7a3a;}\n.ols-sfss-001 .sfss-caption .c-bad{color:#b02a24;}\n.ols-sfss-001 .sfss-caption .c-hi{color:#8a6410;}\n.ols-sfss-001 .sfss-caption{\n  position:absolute; left:14px; top:14px; max-width:60%;\n  font-size:12px; font-weight:500; color:#4a5270; line-height:1.35;\n  background:rgba(255,255,255,0.92); padding:6px 12px;\n  border-radius:14px; border:1px solid rgba(28,36,75,0.12);\n}\n.ols-sfss-001 .sfss-hint{\n  position:absolute; right:14px; top:14px;\n  font-size:11.5px; font-weight:400; color:#8b92a8;\n  background:rgba(255,255,255,0.9); padding:5px 11px;\n  border-radius:999px; border:1px solid rgba(28,36,75,0.10);\n}\n.ols-sfss-001 .sfss-badges{\n  position:absolute; right:14px; bottom:14px; max-width:58%;\n  display:flex; flex-direction:column; align-items:flex-end; gap:6px;\n}\n.ols-sfss-001 .sfss-badge{\n  font-size:12px; font-weight:500; color:#1C244B; line-height:1.35; text-align:right;\n  background:rgba(255,255,255,0.95); padding:5px 12px;\n  border-radius:14px; border:1px solid rgba(28,36,75,0.22);\n}\n.ols-sfss-001 .sfss-badge.b-eq{font-size:13.5px; font-weight:600; border-color:rgba(201,150,28,0.75);}\n\n.ols-sfss-001 .sfss-controls{margin-top:20px; display:flex; flex-direction:column; gap:12px;}\n.ols-sfss-001 .sfss-row{display:flex; align-items:center; gap:10px; flex-wrap:wrap;}\n.ols-sfss-001 .sfss-rowlab{font-size:12px; font-weight:500; color:#6b7290; min-width:100px; flex:0 0 auto;}\n\n.ols-sfss-001 .sfss-seg{\n  display:inline-flex; border:1px solid rgba(28,36,75,0.16);\n  border-radius:12px; overflow:hidden; background:#fbfbfd; flex-wrap:wrap;\n}\n.ols-sfss-001 .sfss-seg button{\n  font-family:inherit; font-size:14px; font-weight:500; color:#3c4463;\n  background:transparent; border:0; border-right:1px solid rgba(28,36,75,0.12);\n  padding:9px 18px; cursor:pointer; transition:background .15s, color .15s;\n}\n.ols-sfss-001 .sfss-seg button:last-child{border-right:0;}\n.ols-sfss-001 .sfss-seg button:hover{background:rgba(37,99,235,0.06);}\n.ols-sfss-001 .sfss-seg button[aria-pressed=\"true\"]{background:#2563eb; color:#fff;}\n.ols-sfss-001 .sfss-seg button:focus-visible{outline:2px solid #2563eb; outline-offset:-2px;}\n\n.ols-sfss-001 .sfss-pill{\n  font-family:inherit; font-size:13px; font-weight:500; color:#3c4463;\n  background:#fbfbfd; border:1px solid rgba(28,36,75,0.16);\n  border-radius:999px; padding:8px 16px; cursor:pointer;\n  display:inline-flex; align-items:center; gap:8px;\n  transition:background .15s, border-color .15s, color .15s;\n}\n.ols-sfss-001 .sfss-pill:hover{border-color:rgba(37,99,235,0.4);}\n.ols-sfss-001 .sfss-pill:focus-visible{outline:2px solid #2563eb; outline-offset:2px;}\n\n.ols-sfss-001 .sfss-info{\n  margin-top:22px; padding:22px 24px;\n  border:1px solid rgba(28,36,75,0.12); border-radius:16px; background:#fbfbfd;\n}\n.ols-sfss-001 .sfss-info h3{margin:0 0 8px; font-size:15.5px; font-weight:600; color:#1C244B;}\n.ols-sfss-001 .sfss-info p{margin:0; font-size:14px; line-height:1.68; font-weight:300; color:#41496a; max-width:74ch;}\n.ols-sfss-001 .sfss-facts{\n  margin-top:16px; display:flex; gap:26px; flex-wrap:wrap;\n  padding-top:16px; border-top:1px solid rgba(28,36,75,0.10);\n}\n.ols-sfss-001 .sfss-fact{min-width:110px;}\n.ols-sfss-001 .sfss-fact span{display:block; font-size:11.5px; color:#7d8399; font-weight:400; margin-bottom:3px;}\n.ols-sfss-001 .sfss-fact strong{display:block; font-size:15px; font-weight:600; color:#1C244B;}\n\n.ols-sfss-001 .sfss-key{\n  margin-top:16px; display:flex; gap:20px; flex-wrap:wrap;\n  font-size:12.5px; font-weight:400; color:#5a6180;\n}\n.ols-sfss-001 .sfss-key i{\n  display:inline-block; width:13px; height:13px; border-radius:3px;\n  margin-right:7px; vertical-align:-2px; border:1px solid rgba(28,36,75,0.18);\n}\n.ols-sfss-001 .sfss-key i.k-ball{border-radius:50%;}\n\n@media (max-width:760px){\n  .ols-sfss-001{padding:26px; border-radius:22px;}\n  .ols-sfss-001 h2.sfss-title{font-size:20.5px;}\n  .ols-sfss-001 p.sfss-sub{font-size:13.5px;}\n  .ols-sfss-001 .sfss-stage{height:400px;}\n  .ols-sfss-001 .sfss-rowlab{min-width:100%;}\n  .ols-sfss-001 .sfss-seg button{padding:9px 13px; font-size:13px;}\n  .ols-sfss-001 .sfss-lab{font-size:10.5px; padding:4px 8px;}\n  .ols-sfss-001 .sfss-lab.l-part{font-size:9.5px; padding:3px 7px;}\n  .ols-sfss-001 .sfss-lab.l-read{font-size:12px; padding:5px 9px;}\n  .ols-sfss-001 .sfss-caption{font-size:10.5px; padding:5px 9px; max-width:64%;}\n  .ols-sfss-001 .sfss-badge{font-size:10.5px; padding:4px 9px;}\n  .ols-sfss-001 .sfss-badge.b-eq{font-size:11px;}\n  .ols-sfss-001 .sfss-badges{max-width:calc(100% - 28px);}\n  .ols-sfss-001 .sfss-info{padding:18px;}\n}\n\/* on a phone the caption needs the full top row, so the drag hint goes *\/\n@media (max-width:480px){\n  .ols-sfss-001 .sfss-hint{display:none;}\n  .ols-sfss-001 .sfss-caption{max-width:calc(100% - 28px);}\n}\n@media (prefers-reduced-motion:reduce){\n  .ols-sfss-001 .sfss-seg button,.ols-sfss-001 .sfss-pill{transition:none;}\n}\n\n.ols-cc-sfss-001{\n  font-family:'Poppins',system-ui,-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;\n  margin:10px auto 0; text-align:center; font-size:11px; font-style:italic; color:#aab0c0;\n}\n.ols-cc-sfss-001 a{color:#aab0c0; text-decoration:none;}\n.ols-cc-sfss-001 a:hover{text-decoration:underline;}\n.ols-sfss-001 .sfss-seg button{display:inline-flex; align-items:center;}\n.ols-sfss-001 .sfss-seg button .sfss-n{display:inline-flex; align-items:center; justify-content:center; width:20px; height:20px; margin-right:9px; border-radius:50%; font-size:11px; font-weight:600; background:rgba(37,99,235,0.10); color:#2563eb; flex:0 0 auto;}\n.ols-sfss-001 .sfss-seg button[aria-pressed=\"true\"] .sfss-n{background:#ffffff; color:#2563eb;}\n<\/style>\n\n<div class=\"sfss-head\">\n  <h2 class=\"sfss-title\">Seesaw Shape of SF\u2084<\/h2>\n  <p class=\"sfss-sub\">Choose a step to watch five electron pairs spread out round sulfur, see why the lone pair picks an equatorial position, and read the squeezed angles.<\/p>\n<\/div>\n\n<div class=\"sfss-stage\" id=\"sfssStage\">\n  <canvas class=\"sfss-canvas\" id=\"sfssCanvas\"><\/canvas>\n  <div class=\"sfss-overlay\" id=\"sfssOverlay\"><\/div>\n  <div class=\"sfss-caption\" id=\"sfssCaption\"><\/div>\n  <div class=\"sfss-hint\" id=\"sfssHint\">Drag to rotate<\/div>\n  <div class=\"sfss-badges\" id=\"sfssBadges\"><\/div>\n<\/div>\n\n<div class=\"sfss-controls\">\n  <div class=\"sfss-row\">\n    <span class=\"sfss-rowlab\">Step<\/span>\n    <div class=\"sfss-seg\" role=\"group\" aria-label=\"Step\">\n      <button type=\"button\" data-step=\"1\" aria-pressed=\"true\"><span class=\"sfss-n\">1<\/span>Five electron pairs<\/button>\n      <button type=\"button\" data-step=\"2\" aria-pressed=\"false\"><span class=\"sfss-n\">2<\/span>Axial or equatorial?<\/button>\n      <button type=\"button\" data-step=\"3\" aria-pressed=\"false\"><span class=\"sfss-n\">3<\/span>Equatorial kept: seesaw<\/button>\n      <button type=\"button\" data-step=\"4\" aria-pressed=\"false\"><span class=\"sfss-n\">4<\/span>102\u00b0, 87\u00b0 and 173\u00b0<\/button>\n    <\/div>\n  <\/div>\n\n  <div class=\"sfss-row\">\n    <span class=\"sfss-rowlab\">View<\/span>\n    <button type=\"button\" class=\"sfss-pill\" id=\"sfssResetV\">Reset view<\/button>\n  <\/div>\n<\/div>\n\n<div class=\"sfss-info\">\n  <h3 id=\"sfssInfoTitle\"><\/h3>\n  <p id=\"sfssInfoText\"><\/p>\n  <div class=\"sfss-facts\" id=\"sfssFacts\"><\/div>\n  <div class=\"sfss-key\">\n    <span><i class=\"k-ball\" style=\"background:#e2c230\"><\/i>Sulfur<\/span>\n    <span><i class=\"k-ball\" style=\"background:#b8de6e\"><\/i>Fluorine<\/span>\n    <span><i class=\"\" style=\"background:rgba(70,128,220,0.45)\"><\/i>Electron pair (bonding)<\/span>\n    <span><i class=\"\" style=\"background:rgba(128,92,214,0.5)\"><\/i>Lone pair<\/span>\n    <span><i class=\"k-ball\" style=\"background:#fac828\"><\/i>Electron<\/span>\n    <span><i class=\"\" style=\"background:#c9961c\"><\/i>Bond angle \/ highlighted bonds<\/span>\n    <span><i class=\"\" style=\"background:#d43a32\"><\/i>Lone pair\u2013bond clash at 90\u00b0<\/span>\n  <\/div>\n<\/div>\n\n<script src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/JS\/sf4-seesaw.js?v=20261025p\"><\/script>\n<\/section>\n\n<p class=\"ols-cc-sfss-001\">&copy; Dr. Mohammed Al-Fatah &#8211; <a href=\"https:\/\/www.onlinelearningsystem.net\" target=\"_blank\" rel=\"noopener\">onlinelearningsystem.net<\/a><\/p>\n\n\n<style>\n  .ols-seesaw-9ch0-page .ols-spec-grid {\n    display: grid;\n    grid-template-columns: repeat(3, minmax(0, 1fr));\n    gap: 14px;\n    margin-top: 18px;\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box {\n    background: #ffffff;\n    border: 1px solid var(--border);\n    border-radius: 18px;\n    padding: 18px;\n    box-shadow: var(--inner-shadow);\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box strong {\n    display: block;\n    font-size: 15px;\n    color: var(--blue);\n    margin-bottom: 6px;\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box span {\n    display: block;\n    font-size: 17px;\n    line-height: 1.55;\n    color: var(--body-text);\n    font-weight: 300;\n    overflow-wrap: anywhere;\n  }\n  .ols-seesaw-9ch0-page .ols-h5p-grid {\n    display: grid;\n    gap: 18px;\n    margin-top: 22px;\n  }\n  .ols-seesaw-9ch0-page .ols-h5p-frame {\n    margin-top: 0;\n  }\n  .ols-seesaw-9ch0-page .ols-formula {\n    white-space: nowrap;\n  }\n  .ols-seesaw-9ch0-page .ols-seesaw-reference-figure .ols-figure-image {\n    min-height: 0;\n    padding: 12px;\n  }\n  .ols-seesaw-9ch0-page .ols-seesaw-reference-figure .ols-figure-image img {\n    width: auto;\n    max-width: 100%;\n    max-height: 320px;\n    object-fit: contain;\n    margin: 0 auto;\n  }\n  @media (max-width: 760px) {\n    .ols-seesaw-9ch0-page .ols-spec-grid {\n      grid-template-columns: 1fr;\n    }\n  }\n<\/style>\n\n<style>\n  .ols-seesaw-9ch0-page .ols-spec-grid {\n    display: grid;\n    grid-template-columns: repeat(3, minmax(0, 1fr));\n    gap: 14px;\n    margin-top: 18px;\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box {\n    background: #ffffff;\n    border: 1px solid var(--border);\n    border-radius: 18px;\n    padding: 18px;\n    box-shadow: var(--inner-shadow);\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box strong {\n    display: block;\n    font-size: 15px;\n    color: var(--blue);\n    margin-bottom: 6px;\n  }\n  .ols-seesaw-9ch0-page .ols-spec-box span {\n    display: block;\n    font-size: 17px;\n    line-height: 1.55;\n    color: var(--body-text);\n    font-weight: 300;\n    overflow-wrap: anywhere;\n  }\n  .ols-seesaw-9ch0-page .ols-h5p-grid {\n    display: grid;\n    gap: 18px;\n    margin-top: 22px;\n  }\n  .ols-seesaw-9ch0-page .ols-h5p-frame {\n    margin-top: 0;\n  }\n  .ols-seesaw-9ch0-page .ols-formula {\n    white-space: nowrap;\n  }\n  .ols-seesaw-9ch0-page .ols-seesaw-reference-figure .ols-figure-image {\n    min-height: 0;\n    padding: 12px;\n  }\n  .ols-seesaw-9ch0-page .ols-seesaw-reference-figure .ols-figure-image img {\n    width: auto;\n    max-width: 100%;\n    max-height: 320px;\n    object-fit: contain;\n    margin: 0 auto;\n  }\n  @media (max-width: 760px) {\n    .ols-seesaw-9ch0-page .ols-spec-grid {\n      grid-template-columns: 1fr;\n    }\n  }\n<\/style>\n\n      <section class=\"ols-h5p-card ols-h5p-inline ols-h5p-recap\">\n<span class=\"ols-h5p-kicker\">Before you start<\/span>\n<h2>GCSE Recap: Electron Pairs in Dot-and-Cross Diagrams<\/h2>\n<p>Before you start, count the electron pairs around the central atom in some GCSE molecules.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"1302\"><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>What SeeSaw Means<\/h2>\n        <\/div>\n        <p>A <strong>SeeSaw<\/strong> molecule has four atoms bonded to a central atom, with the bonded atoms arranged like a tilted seesaw. The shape forms when there are <strong>four bonding pairs<\/strong> and <strong>one lone pair<\/strong> around the central atom.<\/p>\n        <p>The key example for this page is <strong>SF<sub>4<\/sub><\/strong>. Sulfur is the central atom, four fluorine atoms are bonded to sulfur, and sulfur also has one lone pair.<\/p>\n\n        <div class=\"ols-spec-grid\">\n          <div class=\"ols-spec-box\">\n            <strong>Bonding pairs<\/strong>\n            <span>4 bonding pairs around the central atom<\/span>\n          <\/div>\n          <div class=\"ols-spec-box\">\n            <strong>Lone pairs<\/strong>\n            <span>1 lone pair on the central atom<\/span>\n          <\/div>\n          <div class=\"ols-spec-box\">\n            <strong>Bond angles<\/strong>\n            <span>About 102&deg;, 87&deg; and 173&deg; in SF<sub>4<\/sub><\/span>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\"><p><strong>Key idea:<\/strong> four bonding pairs and one lone pair around a central atom give a SeeSaw shape when the lone pair occupies an equatorial position in a trigonal bipyramidal electron-pair arrangement.<\/p><\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Which Species Is SeeSaw-Shaped?<\/h2>\n<p>Count the electrons on each central atom to find the one SeeSaw species.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-217\" class=\"h5p-iframe\" data-content-id=\"217\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SeeSaw Shape MCQ: Four Bonded Atoms but Only One SeeSaw\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">2<\/div>\n          <h2>Why SF<sub>4<\/sub> Is SeeSaw-Shaped<\/h2>\n        <\/div>\n        <p>In SF<sub>4<\/sub>, the central sulfur atom is surrounded by four S-F bonding pairs and one lone pair. This gives five regions of negative charge around sulfur.<\/p>\n        <p>Five electron regions arrange themselves as a <strong>trigonal bipyramidal electron-pair arrangement<\/strong> to minimise repulsion. The lone pair occupies an equatorial position because this gives fewer 90&deg; lone-pair interactions than placing it in an axial position.<\/p>\n        <p>A regular trigonal bipyramid has bond angles of <strong>120&deg;<\/strong> within the equatorial plane, <strong>90&deg;<\/strong> between an axial and an equatorial position and <strong>180&deg;<\/strong> between the two axial positions.<\/p>\n<p>A <strong>lone pair repels more strongly<\/strong> than a bonding pair, so in SF<sub>4<\/sub> these angles close up to about <strong>102&deg;<\/strong>, about <strong>87&deg;<\/strong> and about <strong>173&deg;<\/strong>.<\/p>\n        <p>The <strong>molecular shape<\/strong> only describes the positions of the atoms. Therefore, SF<sub>4<\/sub> is described as <strong>SeeSaw-shaped<\/strong>, even though its electron-pair arrangement is trigonal bipyramidal.<\/p>\n        <div class=\"ols-key-box\"><p><strong>How to count:<\/strong><\/p>\n<ol>\n<li>Start with the <strong>outer-shell electrons<\/strong> of the central atom.<\/li>\n<li>Add one electron for each negative charge and take one away for each positive charge.<\/li>\n<li>Each single bond uses one of those electrons and each double bond uses two. A double or triple bond still counts as <strong>one bonding region<\/strong>.<\/li>\n<li>Divide the electrons left over by two to get the lone pairs.<\/li>\n<\/ol>\n<p>In SF<sub>4<\/sub>: sulfur has <strong>6 outer-shell electrons<\/strong>, the molecule has no charge, and the four S-F single bonds use four of them.<\/p>\n<p>Two are left over, which is one lone pair. Four bonding regions and one lone pair give five regions, so the arrangement is trigonal bipyramidal and the shape is SeeSaw.<\/p>\n<p>For the ion ClF<sub>4<\/sub><sup>+<\/sup>: chlorine has 7 outer-shell electrons, the positive charge takes one away to leave 6, the four bonds use four, and the two left over are again one lone pair.<\/p><\/div>\n\n        <div class=\"ols-figure-card\">\n<div class=\"ols-figure-image\"><img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-cd-19-sf4-seesaw.svg\" alt=\"See-saw SF\u2084 with an equatorial lone pair on sulfur and angles of about 102\u00b0 and 87\u00b0 marked\" width=\"1516\" height=\"906\"><\/div>\n<div class=\"ols-figure-caption\"><p>A SeeSaw species has four bonding regions and one lone pair around the central atom. SF4 is the standard example, with simplified exam-table angles close to 119&deg; and 89&deg;.<\/p><\/div>\n<\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-33-countsf4.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-33-countsf4.jpg\" alt=\"Five-step electron-pair count for SF\u2084 giving four bonding pairs, one lone pair and a see-saw shape\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-33-countsf4.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Sulfur keeps 2 of its 6 outer electrons as one equatorial lone pair: the four F atoms form a see-saw.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Axial or Equatorial?<\/h2>\n<p>Drag the words into the gaps to compare axial and equatorial positions.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-216\" class=\"h5p-iframe\" data-content-id=\"216\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SeeSaw Shape Drag: Why the Lone Pair Goes Equatorial\"><\/iframe><\/div><\/div>\n<\/section>\n\n\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>Electron-Pair Arrangement vs Molecular Shape<\/h2>\n        <\/div>\n        <p>The electron-pair arrangement in SF<sub>4<\/sub> is based on a <strong>trigonal bipyramidal arrangement<\/strong> because there are five electron regions around sulfur.<\/p>\n        <p>The molecular shape is different. Lone pairs are not counted as atoms when naming the shape, so the visible arrangement of the four fluorine atoms is <strong>SeeSaw-shaped<\/strong>.<\/p>\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>Five electron regions<\/h3>\n            <p>Four bonding pairs and one lone pair arrange themselves as far apart as possible around sulfur.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Equatorial lone pair<\/h3>\n            <p>The lone pair occupies an equatorial position in the trigonal bipyramidal arrangement. This reduces the number of close 90&deg; lone-pair interactions.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>SeeSaw bonded atoms<\/h3>\n            <p>The remaining four bonding pairs form two axial bonds and two equatorial bonds, producing a SeeSaw shape.<\/p>\n          <\/div>\n        <\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-21-fivepairs.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-21-fivepairs.jpg\" alt=\"Trigonal bipyramid key with PF\u2085, SF\u2084 and ClF\u2083 sketches showing lone pairs in equatorial positions and their bond angles\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t3-img-21-fivepairs.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Five regions form a trigonal bipyramid; lone pairs take equatorial positions to give the see-saw and distorted T shapes.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Predict a New Molecule<\/h2>\n<p>Work through the shape of a molecule that is not on this page, one step at a time.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-218\" class=\"h5p-iframe\" data-content-id=\"218\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SeeSaw Shape Single Choice: Predicting Tellurium Tetrachloride\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">4<\/div>\n          <h2>SeeSaw Shape Examples<\/h2>\n        <\/div>\n        <p>The SeeSaw shape is found when the central atom has four bonding pairs and one lone pair. The common exam examples include sulfur, selenium, tellurium and iodine or chlorine species with five electron regions around the central atom.<\/p>\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Species<\/th>\n                <th>Central atom<\/th>\n                <th>Electron regions<\/th>\n                <th>Shape<\/th>\n                <th>Bond angles<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Species\">SF<sub>4<\/sub><\/td>\n                <td data-label=\"Central atom\">S<\/td>\n                <td data-label=\"Electron regions\">4 bonding regions, 1 lone pair<\/td>\n                <td data-label=\"Shape\">SeeSaw<\/td>\n                <td data-label=\"Bond angles\">About 102&deg;, 87&deg; and 173&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">SeF<sub>4<\/sub><\/td>\n                <td data-label=\"Central atom\">Se<\/td>\n                <td data-label=\"Electron regions\">4 bonding regions, 1 lone pair<\/td>\n                <td data-label=\"Shape\">SeeSaw<\/td>\n                <td data-label=\"Bond angles\">Slightly less than 120&deg;, 90&deg; and 180&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">TeF<sub>4<\/sub><\/td>\n                <td data-label=\"Central atom\">Te<\/td>\n                <td data-label=\"Electron regions\">4 bonding regions, 1 lone pair<\/td>\n                <td data-label=\"Shape\">SeeSaw<\/td>\n                <td data-label=\"Bond angles\">Slightly less than 120&deg;, 90&deg; and 180&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">IF<sub>4<\/sub><sup>+<\/sup><\/td>\n                <td data-label=\"Central atom\">I<\/td>\n                <td data-label=\"Electron regions\">4 bonding regions, 1 lone pair<\/td>\n                <td data-label=\"Shape\">SeeSaw<\/td>\n                <td data-label=\"Bond angles\">Slightly less than 120&deg;, 90&deg; and 180&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">ClF<sub>4<\/sub><sup>+<\/sup><\/td>\n                <td data-label=\"Central atom\">Cl<\/td>\n                <td data-label=\"Electron regions\">4 bonding regions, 1 lone pair<\/td>\n                <td data-label=\"Shape\">SeeSaw<\/td>\n                <td data-label=\"Bond angles\">Slightly less than 120&deg;, 90&deg; and 180&deg;<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: A SeeSaw with Double Bonds?<\/h2>\n<p>Count the bonding regions and lone pairs in a molecule that contains double bonds.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-655\" class=\"h5p-iframe\" data-content-id=\"655\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SeeSaw Shape MCQ: Counting Regions in XeO\u2082F\u2082\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card orange\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">5<\/div>\n          <h2>How to Explain SeeSaw Shape in an Exam<\/h2>\n        <\/div>\n        <p>A full exam explanation should connect the number of electron regions to electron-pair repulsion, then explain why the lone pair is equatorial and why the bonded atoms form a SeeSaw shape.<\/p>\n\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>1. Identify the central atom<\/h3>\n            <p>For SF<sub>4<\/sub>, the central atom is sulfur.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>2. Count bonding pairs and lone pairs<\/h3>\n            <p>Sulfur has four bonding pairs and one lone pair around it.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>3. Apply electron-pair repulsion<\/h3>\n            <p>The five electron regions arrange themselves as far apart as possible. The lone pair occupies an equatorial position to reduce repulsion.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>4. State the shape and angles<\/h3>\n            <p>The four bonded atoms form a SeeSaw shape. Start from the regular trigonal bipyramidal angles of 120&deg;, 90&deg; and 180&deg;, then state that the equatorial lone pair pushes them in.<\/p>\n<p>In SF<sub>4<\/sub> the equatorial F-S-F angle is about 102&deg;, the axial to equatorial angles are about 87&deg; and the axial to axial angle is about 173&deg;.<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-definition-box\">\n          <p><strong>Exam answer model:<\/strong> SF<sub>4<\/sub> has four bonding pairs and one lone pair around the central sulfur atom. The five electron regions arrange themselves as a trigonal bipyramidal electron-pair arrangement. The lone pair occupies an equatorial position to minimise repulsion.<\/p>\n<p>Therefore, SF<sub>4<\/sub> is SeeSaw-shaped. The lone pair repels more strongly than the bonding pairs, so the angles are reduced from 120&deg;, 90&deg; and 180&deg; to about 102&deg;, about 87&deg; and about 173&deg;.<\/p>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Whose Reasoning Is Right?<\/h2>\n<p>Pick the one fully correct statement in each round.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-219\" class=\"h5p-iframe\" data-content-id=\"219\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"SeeSaw Shape Summary: Whose Reasoning Is Right?\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">6<\/div>\n          <h2>Common Exam Points<\/h2>\n        <\/div>\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>Do not call SF<sub>4<\/sub> trigonal bipyramidal<\/h3>\n            <p>The electron-pair arrangement is trigonal bipyramidal, but the molecular shape is SeeSaw because the lone pair is not counted as an atom.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>State the lone pair is equatorial<\/h3>\n            <p>The lone pair occupies an equatorial position. This reduces repulsion compared with placing the lone pair in an axial position.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Give angles below the ideal values<\/h3>\n            <p>Quote the trigonal bipyramidal angles of 120&deg;, 90&deg; and 180&deg;, then say that the equatorial lone pair reduces them. For SF<sub>4<\/sub>, use about 102&deg;, about 87&deg; and about 173&deg;.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Count around the central atom only<\/h3>\n            <p>The shape is determined by the bonding pairs and lone pairs around the central atom, not by the total number of atoms in the species.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      \n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">\u2713<\/div>\n          <h2>QuickSnap<\/h2>\n        <\/div>\n        <p>The SeeSaw shape is produced when a central atom has <strong>four bonding pairs<\/strong> and <strong>one lone pair<\/strong>. The lone pair occupies an equatorial position in a trigonal bipyramidal electron-pair arrangement, leaving four bonded atoms in a SeeSaw arrangement.<\/p>\n<p>The lone pair repels more strongly than the bonding pairs, so the ideal angles of 120&deg;, 90&deg; and 180&deg; are reduced to about <strong>102&deg;<\/strong>, <strong>87&deg;<\/strong> and <strong>173&deg;<\/strong> in SF<sub>4<\/sub>.<\/p>\n        <div class=\"ols-key-box\"><p><strong>Memory line:<\/strong> 4 bonding pairs + 1 lone pair = SeeSaw = about 102&deg;, 87&deg; and 173&deg;.<\/p><\/div>\n      <\/article>\n\n<section class=\"ols-faq-card\">\n        <h2>SeeSaw FAQs<\/h2>\n        <p>These questions target the points students most often lose marks on when explaining the SeeSaw molecular shape.<\/p>\n        <div class=\"ols-faq-list\">\n          <div class=\"ols-faq-item\">\n            <h3>Why is SF<sub>4<\/sub> SeeSaw-shaped?<\/h3>\n            <p>SF<sub>4<\/sub> is SeeSaw-shaped because sulfur has four bonding pairs and one lone pair. The five electron regions arrange as trigonal bipyramidal, but the lone pair occupies an equatorial position, leaving two axial S-F bonds and two equatorial S-F bonds.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>What are the bond angles in a SeeSaw molecule?<\/h3>\n            <p>Start from the trigonal bipyramidal angles of 120&deg;, 90&deg; and 180&deg;. The equatorial lone pair repels more strongly than the bonding pairs, so in SF<sub>4<\/sub> the angles are reduced to about 102&deg;, about 87&deg; and about 173&deg;.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Is SeeSaw the same as trigonal bipyramidal?<\/h3>\n            <p>No. Trigonal bipyramidal is the electron-pair arrangement for five regions of negative charge. SeeSaw is the molecular shape after the single lone pair is ignored when naming the shape.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why does the lone pair in SF<sub>4<\/sub> occupy an equatorial position?<\/h3>\n            <p>The lone pair occupies an equatorial position because this minimises repulsion. An equatorial lone pair has fewer 90&deg; interactions with bonding pairs than an axial lone pair.<\/p>\n          <\/div>\n        \n<div class=\"ols-faq-item\">\n<h3>How do I tell a SeeSaw shape from a tetrahedral one?<\/h3>\n<p>Both have four bonded atoms. Tetrahedral has no lone pairs and angles of 109.5&deg;. SeeSaw has four bonding pairs plus one lone pair, five regions in a trigonal bipyramid, so SF<sub>4<\/sub> has angles near 102&deg;, 87&deg; and 173&deg;.<\/p>\n<\/div>\n<\/div>\n      <\/section>\n\n      <!-- author card (moved to the end, 10 Oct 2026) -->\n      <div class=\"ols-author\">\n          <img decoding=\"async\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\" alt=\"Dr. Mohammed Al-Fatah\">\n          <div class=\"ols-author-content\">\n            <h2 class=\"ols-author-title\">Written by:<br><span>Dr. Mohammed Al-Fatah<\/span><\/h2>\n            <p class=\"ols-author-description\">Chemistry specialist revision notes for A Level Chemistry.<\/p>\n            <a class=\"ols-linkedin-pill\" href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n              <svg class=\"ols-linkedin-icon\" viewBox=\"0 0 24 24\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M4.98 3.5C4.98 4.88 3.86 6 2.48 6S0 4.88 0 3.5 1.12 1 2.48 1s2.5 1.12 2.5 2.5zM.5 8h4V24h-4V8zm7 0h3.8v2.2h.1c.5-.9 1.8-2.2 3.9-2.2 4.2 0 5 2.8 5 6.4V24h-4v-7.6c0-1.8 0-4.2-2.6-4.2s-3 2-3 4v7.8h-4V8z\"><\/path><\/svg>\n              View LinkedIn Profile\n            <\/a>\n          <\/div>\n        <\/div>\n\n\n      <section class=\"ols-related-card\">\n        <h2>Related Topics<\/h2>\n        <p>Use these related revision notes to strengthen the surrounding bonding and molecular shape ideas.<\/p>\n        <div class=\"ols-related-grid\">\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/trigonal-bipyramidal\/\">Trigonal Bipyramidal<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/distorted-t\/\">Distorted T<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/polar-molecules\/\">Polar &amp; Non-Polar Molecules<\/a>\n        <\/div>\n      <\/section>\n<section class=\"ols-attribution-card ols-attr-std\" aria-label=\"Copyright notice\">\n<style id=\"ols-attribution-card-css\">.ols-attribution-card.ols-attr-std{background:linear-gradient(135deg,#ffffff,#f8fbff);border:1px solid rgba(28,36,75,0.14);border-radius:28px;box-shadow:0 18px 45px rgba(28,36,75,0.10);padding:34px;margin:24px 0;overflow:hidden;font-family:Poppins,Arial,sans-serif;box-sizing:border-box}.ols-attribution-card.ols-attr-std *{box-sizing:border-box}.ols-attribution-card.ols-attr-std p{margin:0;font-size:14px;line-height:1.65;font-weight:300;color:#667085}.ols-attribution-card.ols-attr-std strong{font-weight:700;color:#1C244B}@media (max-width:760px){.ols-attribution-card.ols-attr-std{padding:24px 18px;border-radius:22px}}<\/style>\n<p><strong>Copyright notice:<\/strong> This OLS revision content, including the explanations, layout, diagrams, tables and embedded learning structure, is authored for Online Learning System by Dr. Mohammed Al-Fatah. It may not be copied, reproduced, redistributed or adapted without written permission.<\/p>\n<\/section>\n\n      <div class=\"ols-image-lightbox\" id=\"olsImageLightbox\" aria-hidden=\"true\">\n        <button class=\"ols-image-lightbox-close\" type=\"button\" aria-label=\"Close image\">&times;<\/button>\n        <img decoding=\"async\" src=\"\" alt=\"\">\n      <\/div>\n\n      <script>\n        (function(){\n          var lightbox = document.getElementById(\"olsImageLightbox\");\n          if (!lightbox) { return; }\n\n          var lightboxImage = lightbox.querySelector(\"img\");\n          var closeButton = lightbox.querySelector(\".ols-image-lightbox-close\");\n          var triggers = document.querySelectorAll(\".ols-lightbox-trigger\");\n\n          function closeLightbox() {\n            lightbox.classList.remove(\"is-open\");\n            lightbox.setAttribute(\"aria-hidden\", \"true\");\n            lightboxImage.setAttribute(\"src\", \"\");\n            lightboxImage.setAttribute(\"alt\", \"\");\n          }\n\n          triggers.forEach(function(trigger){\n            trigger.addEventListener(\"click\", function(){\n              lightboxImage.setAttribute(\"src\", trigger.getAttribute(\"data-ols-lightbox-src\"));\n              lightboxImage.setAttribute(\"alt\", trigger.getAttribute(\"data-ols-lightbox-alt\") || \"\");\n              lightbox.classList.add(\"is-open\");\n              lightbox.setAttribute(\"aria-hidden\", \"false\");\n            });\n          });\n\n          closeButton.addEventListener(\"click\", closeLightbox);\n          lightbox.addEventListener(\"click\", function(event){\n            if (event.target === lightbox) { closeLightbox(); }\n          });\n          document.addEventListener(\"keydown\", function(event){\n            if (event.key === \"Escape\") { closeLightbox(); }\n          });\n        })();\n      <\/script>\n\n<script type=\"application\/ld+json\">\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@graph\": [\n        {\n            \"@type\": \"WebPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#webpage\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/\",\n            \"name\": \"SeeSaw Molecular Shape | Edexcel A Level Chemistry\",\n            \"description\": \"Learn the SeeSaw molecular shape for Edexcel A Level Chemistry, using SF4 to explain four bonding pairs, one lone pair, trigonal bipyramidal electron-pair arrangement and bond angles.\",\n            \"inLanguage\": \"en-GB\",\n            \"isPartOf\": {\n                \"@type\": \"WebSite\",\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/#website\",\n                \"name\": \"Online Learning System\",\n                \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/\"\n            },\n            \"about\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#learningresource\"\n            },\n            \"author\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/#dr-mohammed-al-fatah\"\n            },\n            \"primaryImageOfPage\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-62-sf4-see-saw.svg#image\"\n            },\n            \"breadcrumb\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#breadcrumb\"\n            }\n        },\n        {\n            \"@type\": \"Person\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/#dr-mohammed-al-fatah\",\n            \"name\": \"Dr. Mohammed Al-Fatah\",\n            \"url\": \"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\",\n            \"image\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\",\n            \"jobTitle\": \"Chemistry specialist educator\"\n        },\n        {\n            \"@type\": \"ImageObject\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-62-sf4-see-saw.svg#image\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-62-sf4-see-saw.svg\",\n            \"contentUrl\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-62-sf4-see-saw.svg\",\n            \"caption\": \"SeeSaw molecular shape showing four bonding pairs and one lone pair around the central atom.\"\n        },\n        {\n            \"@type\": \"BreadcrumbList\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#breadcrumb\",\n            \"itemListElement\": [\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 1,\n                    \"name\": \"Revision Notes\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 2,\n                    \"name\": \"A Level Chemistry\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 3,\n                    \"name\": \"Edexcel\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 4,\n                    \"name\": \"Topic 2 Bonding and Structure\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 5,\n                    \"name\": \"Shapes of Molecules\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 6,\n                    \"name\": \"SeeSaw\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/\"\n                }\n            ]\n        },\n        {\n            \"@type\": \"LearningResource\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#learningresource\",\n            \"name\": \"SeeSaw Molecular Shape\",\n            \"description\": \"Revision notes explaining the SeeSaw molecular shape using SF4, including electron-pair repulsion, four bonding pairs, one lone pair and approximate bond angles.\",\n            \"learningResourceType\": \"Revision notes\",\n            \"educationalLevel\": \"A Level\",\n            \"teaches\": [\n                \"SeeSaw molecular shape\",\n                \"Electron-pair repulsion theory\",\n                \"SF4 molecular geometry\",\n                \"Bond angles in SeeSaw molecules\"\n            ],\n            \"inLanguage\": \"en-GB\",\n            \"author\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/#dr-mohammed-al-fatah\"\n            }\n        },\n        {\n            \"@type\": \"FAQPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/shapes-of-molecules\/seesaw\/#faq\",\n            \"mainEntity\": [\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"Why is SF4 SeeSaw-shaped?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"SF4 is SeeSaw-shaped because sulfur has four bonding pairs and one lone pair. The five electron regions arrange as trigonal bipyramidal, but the lone pair occupies an equatorial position, leaving two axial S-F bonds and two equatorial S-F bonds.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"What are the bond angles in a SeeSaw molecule?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Start from the trigonal bipyramidal angles of 120\u00b0, 90\u00b0 and 180\u00b0. The equatorial lone pair repels more strongly than the bonding pairs, so in SF4 the angles are reduced to about 102\u00b0, about 87\u00b0 and about 173\u00b0.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"Is SeeSaw the same as trigonal bipyramidal?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"No. Trigonal bipyramidal is the electron-pair arrangement for five regions of negative charge. SeeSaw is the molecular shape after the single lone pair is ignored when naming the shape.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"Why does the lone pair in SF4 occupy an equatorial position?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"The lone pair occupies an equatorial position because this minimises repulsion. An equatorial lone pair has fewer 90\u00b0 interactions with bonding pairs than an axial lone pair.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"How do I tell a SeeSaw shape from a tetrahedral one?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Both have four bonded atoms. Tetrahedral has no lone pairs and angles of 109.5\u00b0. SeeSaw has four bonding pairs plus one lone pair, five regions in a trigonal bipyramid, so SF4 has angles near 102\u00b0, 87\u00b0 and 173\u00b0.\"\n                    }\n                }\n            ]\n        }\n    ]\n}\n<\/script>\n    <\/main>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Revision Notes \/ A Level Chemistry \/ Edexcel \/ Topic 2 Bonding and Structure \/ Shapes of Molecules \/ SeeSaw SeeSaw Molecular Shape A focused revision guide to the SeeSaw molecular shape, using SF4 as the key example. This page explains why four bonding pairs and one lone pair around a central atom give a [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"parent":4572,"menu_order":10,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4595","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4595","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/comments?post=4595"}],"version-history":[{"count":2,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4595\/revisions"}],"predecessor-version":[{"id":24945,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4595\/revisions\/24945"}],"up":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4572"}],"wp:attachment":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/media?parent=4595"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}