{"id":7700,"date":"2026-09-12T11:57:10","date_gmt":"2026-09-12T10:57:10","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/trigonal-planar\/"},"modified":"2026-09-26T10:23:59","modified_gmt":"2026-09-26T09:23:59","slug":"trigonal-planar","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/trigonal-planar\/","title":{"rendered":"Trigonal Planar Molecular Shape"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-trigonal-planar-molecular-shape-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      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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  <\/style>\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>Cambridge International AS Level Chemistry<\/p>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>3.5 Shapes of Molecules<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/\">Part overview<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/linear\/\">Linear<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/trigonal-planar\/\">Trigonal Planar<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/tetrahedral\/\">Tetrahedral<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/trigonal-pyramidal\/\">Trigonal Pyramidal<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/bent\/\">Bent<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/trigonal-bipyramidal\/\">Trigonal Bipyramidal<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/octahedral\/\">Octahedral<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/square-planar\/\">Square Planar<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/square-pyramidal\/\">Square Pyramidal<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/distorted-t\/\">Distorted T<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/seesaw\/\">SeeSaw<\/a><\/li>\n    <\/ul>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>Other Topic 3 Parts<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/\">Topic 3 overview<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/electronegativity\/\">3.1 Electronegativity<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/covalent-bonding\/\">3.4 Covalent Bonding<\/a><\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\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, 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href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/\">Topic 3 Chemical Bonding<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/\">3.5 Shapes of Molecules<\/a> \/\n<span>Trigonal Planar Molecular Shape<\/span>\n<\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Trigonal Planar Molecular Shape<\/h1>\n        <p class=\"ols-page-intro\">A focused revision guide to the trigonal planar molecular shape, using BCl<sub>3<\/sub> as the key example. This page explains why three bonding pairs and no lone pairs around a central atom give 120&deg; bond angles in one flat plane.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">AS Level<\/div>\n<div class=\"ols-badge\">Topic 3: Chemical Bonding<\/div>\n<div class=\"ols-badge\">9701 Papers 1 and 2<\/div>\n        <\/div>\n\n                <div class=\"ols-author\">\n\n    <img decoding=\"async\"\n      class=\"ols-author-avatar-img\"\n      src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\"\n      alt=\"Dr. Mohammed Al-Fatah\"\n    >\n\n    <div class=\"ols-author-content\">\n\n      <h2 class=\"ols-author-title\">\n        Written by: Dr. Mohammed Al-Fatah\n      <\/h2>\n\n      <p class=\"ols-author-description\">\n        Chemistry specialist revision notes for A Level Chemistry.\n      <\/p>\n\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\">\n          <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\"\/>\n        <\/svg>\n        View LinkedIn Profile\n      <\/a>\n\n    <\/div>\n\n  <\/div>\n      <\/header>\n\n<style>\n  .ols-trigonal-planar-molecular-shape-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-trigonal-planar-molecular-shape-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-trigonal-planar-molecular-shape-9ch0-page .ols-spec-box strong {\n    display: block;\n    font-size: 15px;\n    color: var(--blue);\n    margin-bottom: 6px;\n  }\n  .ols-trigonal-planar-molecular-shape-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-trigonal-planar-molecular-shape-9ch0-page .ols-h5p-grid {\n    display: grid;\n    gap: 18px;\n    margin-top: 22px;\n  }\n  .ols-trigonal-planar-molecular-shape-9ch0-page .ols-h5p-frame {\n    margin-top: 0;\n  }\n  .ols-trigonal-planar-molecular-shape-9ch0-page .ols-formula {\n    white-space: nowrap;\n  }\n  @media (max-width: 760px) {\n    .ols-trigonal-planar-molecular-shape-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: Double Covalent Bonds<\/h2>\n<p>Before you start, check that you remember what a double covalent bond is and where its electrons are.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"677\"><\/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 Trigonal Planar Means<\/h2>\n        <\/div>\n        <p>A <strong>trigonal planar<\/strong> molecule has three atoms arranged around a central atom in a flat triangular pattern. The word <strong>trigonal<\/strong> means three positions around the central atom, and <strong>planar<\/strong> means all the atoms lie in the same plane.<\/p>\n        <p>The key example for this page is <strong>BCl<sub>3<\/sub><\/strong>. Boron is the central atom and each chlorine atom is attached to boron by a covalent bond.<\/p>\n\n        <div class=\"ols-spec-grid\">\n          <div class=\"ols-spec-box\">\n            <strong>Bonding pairs<\/strong>\n            <span>3 bonding pairs around the central atom<\/span>\n          <\/div>\n          <div class=\"ols-spec-box\">\n            <strong>Lone pairs<\/strong>\n            <span>0 lone pairs on the central atom<\/span>\n          <\/div>\n          <div class=\"ols-spec-box\">\n            <strong>Bond angle<\/strong>\n            <span>120&deg; between each bond<\/span>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\"><p><strong>Key idea:<\/strong> three bonding regions and no lone pairs around a central atom give a trigonal planar shape with 120&deg; bond angles.<\/p><\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">2<\/div>\n          <h2>Why BCl<sub>3<\/sub> Is Trigonal Planar<\/h2>\n        <\/div>\n        <p>In BCl<sub>3<\/sub>, the central boron atom is surrounded by three B-Cl bonding pairs. These bonding pairs are regions of negative charge, so they repel each other and move as far apart as possible.<\/p>\n        <p>With three equal bonding regions and no lone pairs, the maximum separation is achieved when the bonds are spread evenly in one plane. This places each B-Cl bond <strong>120&deg;<\/strong> from the next.<\/p>\n\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: Why Flat?<\/h2>\n<p>Use the idea of maximum separation to explain the shape of a molecule you have not met on this page.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-181\" class=\"h5p-iframe\" data-content-id=\"181\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Trigonal Planar MCQ: Why Borane Is Flat and Not a Pyramid\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <div class=\"ols-zoom-card compact\">\n        <div class=\"ols-zoom-card-image\">\n          <img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/bcl3.png\" alt=\"Displayed formula of boron trichloride showing boron bonded to three chlorine atoms in a trigonal planar arrangement\" class=\"ols-zoomable-img ols-lightbox-target\" draggable=\"false\">\n        <\/div>\n        <div class=\"ols-zoom-card-caption\">\n          <p>BCl<sub>3<\/sub> has three B-Cl bonds around boron and no lone pairs on the central atom, so the three bonds spread out evenly.<\/p>\n        <\/div>\n      <\/div>\n\n      <!-- 3D card: bcl3-trigonal-planar (swapped 26 Sep 2026) -->\n<section class=\"ols-tpl-001\" id=\"olsTpl001\">\n<style>\n@import url('https:\/\/fonts.googleapis.com\/css2?family=Poppins:wght@300;400;500;600&display=swap');\n\n.ols-tpl-001{\n  font-family:'Poppins',system-ui,-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;\n  color:#1C244B; 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has no lone pairs\"><i class=\"dot\"><\/i>Lone pairs<\/button>\n    <button type=\"button\" class=\"tpl-pill p-gold\" id=\"tplTogAng\" aria-pressed=\"true\"><i class=\"dot\"><\/i>Bond angles<\/button>\n    <button type=\"button\" class=\"tpl-pill\" id=\"tplTogLab\" aria-pressed=\"true\"><i class=\"dot\"><\/i>Labels<\/button>\n    <button type=\"button\" class=\"tpl-pill\" id=\"tplTogCloud\" aria-pressed=\"false\"><i class=\"dot\"><\/i>Electron-pair cloud outline<\/button>\n  <\/div>\n\n  <div class=\"tpl-row\">\n    <span class=\"tpl-rowlab\">Motion<\/span>\n    <button type=\"button\" class=\"tpl-pill\" id=\"tplSpin\" aria-pressed=\"false\"><i class=\"dot\"><\/i>Rotation<\/button>\n    <button type=\"button\" class=\"tpl-pill\" id=\"tplResetV\">Reset view<\/button>\n  <\/div>\n<\/div>\n\n<div class=\"tpl-info\">\n  <h3 id=\"tplInfoTitle\"><\/h3>\n  <p id=\"tplInfoText\"><\/p>\n  <div class=\"tpl-facts\" id=\"tplFacts\"><\/div>\n  <div class=\"tpl-key\">\n    <span><i style=\"background:rgba(59,120,220,0.45)\"><\/i>Electron pair<\/span>\n    <span><i style=\"background:#484e5c\"><\/i>Boron, central atom<\/span>\n    <span><i style=\"background:#3aa048\"><\/i>Chlorine<\/span>\n    <span><i style=\"background:#8c92a0\"><\/i>Bond<\/span>\n    <span><i style=\"background:#c9961c\"><\/i>Bond angle<\/span>\n  <\/div>\n<\/div>\n<\/section>\n\n<p class=\"ols-cc-tpl-001\">&copy; Dr. Mohammed Al-Fatah &#8211; <a href=\"https:\/\/www.onlinelearningsystem.net\" target=\"_blank\" rel=\"noopener\">onlinelearningsystem.net<\/a><\/p>\n\n<script src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/JS\/bcl3-trigonal-planar.js?v=20260926\"><\/script>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>Bonding Pairs, Lone Pairs and Bond Angle<\/h2>\n        <\/div>\n        <p>The shape is decided by the number of electron domains around the central atom. In a simple shape question, each single bond counts as one bonding region. BCl<sub>3<\/sub> has three bonding regions around boron and no lone pair regions on boron.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Feature<\/th>\n                <th>Trigonal planar value<\/th>\n                <th>Meaning in BCl<sub>3<\/sub><\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Feature\">Number of bonding pairs<\/td>\n                <td data-label=\"Trigonal planar value\">3<\/td>\n                <td data-label=\"Meaning in BCl3\">Three B-Cl bonding pairs repel each other equally.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Feature\">Number of lone pairs<\/td>\n                <td data-label=\"Trigonal planar value\">0<\/td>\n                <td data-label=\"Meaning in BCl3\">No lone pair compression occurs, so the ideal angle is maintained.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Feature\">Bond angle<\/td>\n                <td data-label=\"Trigonal planar value\">120&deg;<\/td>\n                <td data-label=\"Meaning in BCl3\">The three bonds are evenly spaced in a flat triangular arrangement.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Feature\">Molecular shape<\/td>\n                <td data-label=\"Trigonal planar value\">Trigonal planar<\/td>\n                <td data-label=\"Meaning in BCl3\">All four atoms lie in one plane.<\/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: Count the Regions<\/h2>\n<p>Work through the electron count for two new molecules and type a number in each gap.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-182\" class=\"h5p-iframe\" data-content-id=\"182\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Trigonal Planar Fill in the Blanks: Counting Regions in GaCl\u2083 and COCl\u2082\"><\/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>Examples of Trigonal Planar Species<\/h2>\n        <\/div>\n        <p>Several molecules and ions use the same three-region arrangement around the central atom. The examples from this shape table include <strong>BF<sub>3<\/sub><\/strong>, <strong>AlCl<sub>3<\/sub><\/strong>, <strong>SO<sub>3<\/sub><\/strong>, <strong>NO<sub>3<\/sub><sup>&#8211;<\/sup><\/strong> and <strong>CO<sub>3<\/sub><sup>2-<\/sup><\/strong>.<\/p>\n        <p>For exam purposes, focus on the central atom, count the electron domains around it, then state the shape and bond angle.<\/p>\n\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 around central atom<\/th>\n                <th>Shape<\/th>\n                <th>Bond angle<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Species\">BF<sub>3<\/sub><\/td>\n                <td data-label=\"Central atom\">B<\/td>\n                <td data-label=\"Electron regions\">3 bonding regions, 0 lone pairs<\/td>\n                <td data-label=\"Shape\">Trigonal planar<\/td>\n                <td data-label=\"Bond angle\">120&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">AlCl<sub>3<\/sub><\/td>\n                <td data-label=\"Central atom\">Al<\/td>\n                <td data-label=\"Electron regions\">3 bonding regions, 0 lone pairs<\/td>\n                <td data-label=\"Shape\">Trigonal planar<\/td>\n                <td data-label=\"Bond angle\">120&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">SO<sub>3<\/sub><\/td>\n                <td data-label=\"Central atom\">S<\/td>\n                <td data-label=\"Electron regions\">3 bonding regions, 0 lone pairs<\/td>\n                <td data-label=\"Shape\">Trigonal planar<\/td>\n                <td data-label=\"Bond angle\">120&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">NO<sub>3<\/sub><sup>&#8211;<\/sup><\/td>\n                <td data-label=\"Central atom\">N<\/td>\n                <td data-label=\"Electron regions\">3 bonding regions, 0 lone pairs<\/td>\n                <td data-label=\"Shape\">Trigonal planar<\/td>\n                <td data-label=\"Bond angle\">120&deg;<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Species\">CO<sub>3<\/sub><sup>2-<\/sup><\/td>\n                <td data-label=\"Central atom\">C<\/td>\n                <td data-label=\"Electron regions\">3 bonding regions, 0 lone pairs<\/td>\n                <td data-label=\"Shape\">Trigonal planar<\/td>\n                <td data-label=\"Bond angle\">120&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: Trigonal Planar or Not?<\/h2>\n<p>Count the electrons left over on each central atom and decide quickly whether the species is trigonal planar.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-180\" class=\"h5p-iframe\" data-content-id=\"180\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Trigonal Planar Single Choice: Trigonal Planar or Not?\"><\/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 Trigonal Planar Shape in an Exam<\/h2>\n        <\/div>\n        <p>A full exam explanation should name the electron pairs around the central atom and connect this directly to repulsion and angle.<\/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 BCl<sub>3<\/sub>, the central atom is boron.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>2. Count bonding pairs and lone pairs<\/h3>\n            <p>Boron has three bonding pairs and no lone pairs around it.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>3. Apply electron-pair repulsion<\/h3>\n            <p>The three bonding pairs repel equally and move as far apart as possible.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>4. State the shape and angle<\/h3>\n            <p>The molecule is trigonal planar with bond angles of 120&deg;.<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-definition-box\">\n          <p><strong>Exam answer model:<\/strong> BCl<sub>3<\/sub> has three bonding pairs and no lone pairs around the central boron atom. The bonding pairs repel equally and arrange themselves as far apart as possible in one plane. Therefore, BCl<sub>3<\/sub> is trigonal planar with bond angles of 120&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: Write the Exam Answer<\/h2>\n<p>Write a short exam-style explanation for a new ion, then compare it with the mark points and the model answer.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-183\" class=\"h5p-iframe\" data-content-id=\"183\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Trigonal Planar Explain: Shape and Bond Angle of the Methyl Cation\"><\/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        <p>Trigonal planar questions often test whether you can distinguish between the number of atoms attached to the central atom and the number of electron domains around the central atom.<\/p>\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>Do not write 109.5&deg;<\/h3>\n            <p>109.5&deg; is the tetrahedral angle. Trigonal planar species have three electron regions and an ideal angle of 120&deg;.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Do not add a lone pair to boron in BCl<sub>3<\/sub><\/h3>\n            <p>For this shape model, boron has three bonding pairs and no lone pairs around the central atom.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>State \u201cin one plane\u201d when useful<\/h3>\n            <p>The planar part of trigonal planar means the atoms lie in a flat arrangement.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Use electron-pair repulsion language<\/h3>\n            <p>Marks usually require the idea that bonding pairs repel and arrange themselves as far apart as possible.<\/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 trigonal planar shape is produced when a central atom has <strong>three bonding pairs<\/strong> and <strong>no lone pairs<\/strong>. The bonding pairs repel equally and spread out evenly in one plane, giving <strong>120&deg;<\/strong> bond angles.<\/p>\n        <div class=\"ols-key-box\"><p><strong>Memory line:<\/strong> 3 bonding pairs + 0 lone pairs = trigonal planar = 120&deg;.<\/p><\/div>\n      <\/article>\n\n            <section class=\"ols-course-cta-covalent\" id=\"olsCourseCtaCovalent001\">\r\n  <style>\r\n    .ols-course-cta-covalent,\r\n    .ols-course-cta-covalent * {\r\n      box-sizing: border-box;\r\n    }\r\n\r\n    .ols-course-cta-covalent {\r\n      --navy: #1C244B;\r\n      --blue: #2563eb;\r\n      --body-text: #1f2937;\r\n      --grey-text: #667085;\r\n      --border: rgba(28, 36, 75, 0.14);\r\n      --shadow: 0 18px 45px rgba(28, 36, 75, 0.12);\r\n      --inner-shadow: 0 10px 26px rgba(28, 36, 75, 0.08);\r\n\r\n      width: 100%;\r\n      margin: 30px 0 24px;\r\n      font-family: Poppins, Arial, sans-serif;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-cta-card {\r\n      overflow: 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center;\r\n      justify-content: center;\r\n      padding: 15px 28px;\r\n      border-radius: 999px;\r\n      background: var(--navy);\r\n      color: #ffffff;\r\n      text-decoration: none;\r\n      font-size: 16px;\r\n      line-height: 1.2;\r\n      font-weight: 800;\r\n      box-shadow: 0 12px 26px rgba(28, 36, 75, 0.18);\r\n      transition:\r\n        transform 0.2s ease,\r\n        background 0.2s ease,\r\n        box-shadow 0.2s ease;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-button:hover {\r\n      transform: translateY(-2px);\r\n      background: var(--blue);\r\n      color: #ffffff;\r\n      box-shadow: 0 16px 32px rgba(37, 99, 235, 0.24);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-button-top {\r\n      flex-shrink: 0;\r\n      padding: 12px 22px;\r\n      font-size: 15px;\r\n    }\r\n\r\n    @media (max-width: 900px) {\r\n      .ols-course-cta-covalent .ols-course-cta-top {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-cta-image-link {\r\n        max-width: 520px;\r\n        margin: 0 auto;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-cta-intro-stats {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-animation-frame-shell {\r\n        height: 520px;\r\n      }\r\n    }\r\n\r\n    @media (max-width: 760px) {\r\n      .ols-course-cta-covalent {\r\n        margin: 26px 0 22px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-cta-card {\r\n        padding: 20px;\r\n        border-radius: 24px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-cta-header-row {\r\n        align-items: stretch;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-button-top {\r\n        width: 100%;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-cta-stats,\r\n      .ols-course-cta-covalent .ols-course-cta-features {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-animation-wrap {\r\n        padding: 0;\r\n        border-radius: 0;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-animation-frame-shell {\r\n        height: 420px;\r\n        border-radius: 18px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-animation-play-circle {\r\n        width: 76px;\r\n        height: 76px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-animation-play-icon {\r\n        border-top-width: 14px;\r\n        border-bottom-width: 14px;\r\n        border-left-width: 22px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-animation-pause-button {\r\n        left: 12px;\r\n        bottom: 12px;\r\n        min-width: 84px;\r\n        padding: 9px 14px;\r\n        font-size: 13px;\r\n      }\r\n\r\n      .ols-course-cta-covalent .ols-course-button {\r\n        width: 100%;\r\n      }\r\n    }\r\n  <\/style>\r\n\r\n  <div class=\"ols-course-cta-card\">\r\n\r\n    <div class=\"ols-course-cta-top\">\r\n\r\n      <a class=\"ols-course-cta-image-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/covalent-bonding-and-shapes-of-molecules-topic-3-cambridge-international\/\" aria-label=\"Open the Cambridge International AS and A Level Chemistry Topic 3 Covalent Bonding and Shapes of Molecules course page\">\r\n\r\n        <div class=\"ols-course-cta-image\">\r\n          <img decoding=\"async\"\r\n            src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/cambridge-international-a-level-chemistry-topic-3-covalent-bonding-shapes-interactive-course-banner.jpg\"\r\n            alt=\"Cambridge International AS and A Level Chemistry Topic 3 Covalent Bonding and Shapes of Molecules interactive course banner\"\r\n          >\r\n        <\/div>\r\n\r\n      <\/a>\r\n\r\n      <div class=\"ols-course-cta-content\">\r\n\r\n        <div class=\"ols-course-cta-header-row\">\r\n\r\n          <div class=\"ols-course-cta-kicker\">\r\n            Cambridge 9701 | Topic 3 Course\r\n          <\/div>\r\n\r\n          <a class=\"ols-course-button ols-course-button-top\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/covalent-bonding-and-shapes-of-molecules-topic-3-cambridge-international\/\">\r\n            View Course\r\n          <\/a>\r\n\r\n        <\/div>\r\n\r\n        <h2>\r\n          Master Covalent Bonding and Shapes of Molecules for Cambridge International AS &amp; A Level Chemistry\r\n        <\/h2>\r\n\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-intro-stats\">\r\n\r\n      <p class=\"ols-course-cta-intro\">\r\n        Continue from these free revision notes into the full Topic 3 Covalent Bonding and Shapes of Molecules course. The guided video lessons are ready now; the Cambridge International MCQ bank, teacher-marked short-answer questions and KASP spec-point report are being written, and the course opens for enrolment as soon as they are complete.\r\n      <\/p>\r\n\r\n      <div class=\"ols-course-cta-stats\">\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>Recorded lessons<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>Video lessons<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>MCQ practice<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>SAQ practice<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-features\">\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Guided video teaching<\/h3>\r\n        <p>\r\n          Learn the chemistry and exam technique through structured video lessons with worked examples and walkthroughs.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Instant MCQ feedback<\/h3>\r\n        <p>\r\n          Auto-marked MCQ quizzes provide immediate diagnostic feedback for every answer choice.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Teacher-marked SAQs<\/h3>\r\n        <p>\r\n          Submit written exam responses and receive chemistry specialist feedback with improvement guidance.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Progress tracking<\/h3>\r\n        <p>\r\n          Identify strengths and weaknesses across the full Topic 3 specification with targeted reporting.\r\n        <\/p>\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-animation-wrap\">\r\n\r\n      <h3 class=\"ols-course-animation-title\">\r\n        See how the course works\r\n      <\/h3>\r\n\r\n      <div class=\"ols-animation-frame-shell\">\r\n        <iframe\r\n          id=\"olsCourseAnimationFrame001\"\r\n          title=\"OLS course preview animation\"\r\n          loading=\"lazy\"\r\n          referrerpolicy=\"no-referrer\">\r\n        <\/iframe>\r\n\r\n        <button\r\n          class=\"ols-animation-start-overlay\"\r\n          id=\"olsCourseAnimationStart001\"\r\n          type=\"button\"\r\n          aria-label=\"Play OLS course preview animation\">\r\n          <span class=\"ols-animation-start-content\">\r\n            <span class=\"ols-animation-play-circle\" aria-hidden=\"true\">\r\n              <span class=\"ols-animation-play-icon\"><\/span>\r\n            <\/span>\r\n            <span class=\"ols-animation-start-text\">\r\n              Play course preview animation\r\n            <\/span>\r\n          <\/span>\r\n        <\/button>\r\n\r\n        <button\r\n          class=\"ols-animation-pause-button\"\r\n          id=\"olsCourseAnimationPause001\"\r\n          type=\"button\"\r\n          aria-label=\"Pause course preview animation\">\r\n          Pause\r\n        <\/button>\r\n      <\/div>\r\n\r\n      <p class=\"ols-course-video-status\">\r\n        Click play to start the course preview animation.\r\n      <\/p>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-bottom\">\r\n\r\n      <a class=\"ols-course-button\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/covalent-bonding-and-shapes-of-molecules-topic-3-cambridge-international\/\">\r\n        View Covalent Bonding and Shapes of Molecules Course\r\n      <\/a>\r\n\r\n    <\/div>\r\n\r\n  <\/div>\r\n\r\n  <template id=\"olsCourseAnimationTemplate001\">\r\n<!DOCTYPE html>\r\n<html lang=\"en\">\r\n<head>\r\n<meta charset=\"UTF-8\">\r\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\r\n<title>OLS Combined Promo Animation<\/title>\r\n\r\n<style>\r\n*{box-sizing:border-box;}\r\n\r\nhtml.ols-animation-paused *,\r\nhtml.ols-animation-paused *::before,\r\nhtml.ols-animation-paused *::after{\r\n  animation-play-state:paused!important;\r\n}\r\n\r\n:root{\r\n  --ols-video-screen-w:1180;\r\n  --ols-video-screen-h:664;\r\n  --ols-video-screen-scale:1;\r\n  --ols-mcq-screen-w:1360;\r\n  --ols-mcq-screen-h:1130;\r\n  --ols-mcq-screen-scale:1;\r\n  --ols-saq-screen-w:1360;\r\n  --ols-saq-screen-h:965;\r\n  --ols-saq-screen-scale:1;\r\n}\r\n\r\nhtml,\r\nbody{\r\n  width:100%;\r\n  height:100%;\r\n}\r\n\r\nbody{\r\n  margin:0;\r\n  overflow:hidden;\r\n  font-family:Poppins,Arial,sans-serif;\r\n  background:#e9efff;\r\n}\r\n\r\n.ols-combined-stage{\r\n  position:relative;\r\n  width:100vw;\r\n  height:100vh;\r\n  overflow:hidden;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n}\r\n\r\n.ols-scene{\r\n  position:absolute;\r\n  inset:0;\r\n  width:100vw;\r\n  height:100vh;\r\n  opacity:0;\r\n  visibility:hidden;\r\n  pointer-events:none;\r\n}\r\n\r\n.ols-scene.active{\r\n  opacity:1;\r\n  visibility:visible;\r\n  pointer-events:auto;\r\n}\r\n\r\n.ols-scene.fade-out{\r\n  animation:olsSceneFadeOut 0.85s ease forwards;\r\n}\r\n\r\n@keyframes olsSceneFadeOut{\r\n  to{\r\n    opacity:0;\r\n    visibility:hidden;\r\n  }\r\n}\r\n\r\n.ols-title-cursor{\r\n  display:inline-block;\r\n  width:5px;\r\n  height:0.85em;\r\n  background:#1C244B;\r\n  margin-left:8px;\r\n  transform:translateY(8px);\r\n  animation:olsBlink 0.8s infinite;\r\n}\r\n\r\n.cursor{\r\n  display:inline-block;\r\n  width:3px;\r\n  height:28px;\r\n  background:#1c244b;\r\n  margin-left:3px;\r\n  transform:translateY(5px);\r\n  animation:olsBlink 0.8s infinite;\r\n}\r\n\r\n@keyframes olsBlink{\r\n  0%,45%{opacity:1;}\r\n  46%,100%{opacity:0;}\r\n}\r\n\r\n.ols-video-stage,\r\n.ols-mcq-stage,\r\n.ols-saq-stage{\r\n  width:100vw;\r\n  height:100vh;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  padding:0;\r\n  overflow:hidden;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n}\r\n\r\n.ols-video-title-screen,\r\n.ols-mcq-intro-screen,\r\n.ols-saq-intro{\r\n  position:absolute;\r\n  inset:0;\r\n  z-index:50;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n  opacity:1;\r\n  visibility:visible;\r\n  pointer-events:none;\r\n}\r\n\r\n.ols-video-title-screen.hide{animation:olsVideoTitleFadeOut 0.85s ease forwards;}\r\n.ols-mcq-intro-screen.hide{animation:olsMcqIntroFadeOut 0.85s ease forwards;}\r\n.ols-saq-intro.hide{animation:olsSaqIntroFadeOut 0.85s ease forwards;}\r\n\r\n@keyframes olsVideoTitleFadeOut{to{opacity:0;visibility:hidden;}}\r\n@keyframes olsMcqIntroFadeOut{to{opacity:0;visibility:hidden;}}\r\n@keyframes olsSaqIntroFadeOut{to{opacity:0;visibility:hidden;}}\r\n\r\n.ols-video-title-wrap,\r\n.ols-mcq-intro-title-wrap,\r\n.ols-saq-intro-title-wrap{\r\n  max-width:1250px;\r\n  padding:0 34px;\r\n  text-align:center;\r\n}\r\n\r\n.ols-video-title,\r\n.ols-mcq-intro-title,\r\n.ols-saq-intro-title{\r\n  margin:0;\r\n  font-family:Poppins,Arial,sans-serif;\r\n  font-size:clamp(52px,8vw,124px);\r\n  font-weight:600;\r\n  line-height:1.08;\r\n  color:#1C244B;\r\n  text-shadow:-9px 0 9px rgba(28,36,75,0.16);\r\n  letter-spacing:-0.045em;\r\n}\r\n\r\n#videoTitleText,\r\n#mcqIntroTitleText,\r\n#saqIntroTitleText{\r\n  white-space:pre-wrap;\r\n}\r\n\r\n.ols-video-scene{\r\n  width:100%;\r\n  height:100%;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  opacity:0;\r\n  visibility:hidden;\r\n}\r\n\r\n.ols-video-scene.show{\r\n  visibility:visible;\r\n  animation:olsVideoSceneIn 1s ease forwards;\r\n}\r\n\r\n@keyframes olsVideoSceneIn{to{opacity:1;}}\r\n\r\n.ols-video-scale-wrap{\r\n  width:calc(var(--ols-video-screen-w) * 1px);\r\n  height:calc(var(--ols-video-screen-h) * 1px);\r\n  transform:scale(var(--ols-video-screen-scale));\r\n  transform-origin:center center;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n}\r\n\r\n.ols-video-card{\r\n  width:1180px;\r\n  height:664px;\r\n  border-radius:28px;\r\n  overflow:hidden;\r\n  background:#1C244B;\r\n  box-shadow:0 28px 80px rgba(28,36,75,0.28);\r\n  transform:translateY(24px) scale(0.96);\r\n  opacity:0;\r\n}\r\n\r\n.ols-video-scene.show .ols-video-card{\r\n  animation:olsVideoCardIn 1s cubic-bezier(.18,.89,.32,1.12) forwards;\r\n  animation-delay:0.2s;\r\n}\r\n\r\n@keyframes olsVideoCardIn{\r\n  to{\r\n    transform:translateY(0) scale(1);\r\n    opacity:1;\r\n  }\r\n}\r\n\r\n.ols-video-card video{\r\n  display:block;\r\n  width:100%;\r\n  height:100%;\r\n  aspect-ratio:16 \/ 9;\r\n  object-fit:cover;\r\n  border:0;\r\n}\r\n\r\n.ols-mcq-scale-wrap,\r\n.ols-saq-scale-wrap{\r\n  width:calc(var(--ols-mcq-screen-w) * 1px);\r\n  height:calc(var(--ols-mcq-screen-h) * 1px);\r\n  transform:scale(var(--ols-mcq-screen-scale));\r\n  transform-origin:center center;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:flex-start;\r\n}\r\n\r\n.ols-saq-scale-wrap{\r\n  width:calc(var(--ols-saq-screen-w) * 1px);\r\n  height:calc(var(--ols-saq-screen-h) * 1px);\r\n  transform:scale(var(--ols-saq-screen-scale));\r\n}\r\n\r\n.ols-mcq-screen{\r\n  width:1360px;\r\n  height:1130px;\r\n  border-radius:22px;\r\n  overflow:hidden;\r\n  background:#eaf0ff;\r\n  box-shadow:0 26px 70px rgba(28,36,75,0.22);\r\n  opacity:0;\r\n  transform:translateY(24px) scale(0.96);\r\n}\r\n\r\n.ols-mcq-screen.show{\r\n  animation:olsMcqScreenEnter 1s ease forwards;\r\n}\r\n\r\n@keyframes olsMcqScreenEnter{\r\n  from{opacity:0;transform:translateY(24px) scale(0.96);}\r\n  to{opacity:1;transform:translateY(0) scale(1);}\r\n}\r\n\r\n.mcq-question-area{\r\n  background:#eaf0ff;\r\n  padding:28px 30px 30px;\r\n  position:relative;\r\n  height:610px;\r\n}\r\n\r\n.mcq-question-lead{\r\n  margin:0 0 14px;\r\n  font-size:24px;\r\n  line-height:1.35;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-ionic-table{\r\n  border-collapse:collapse;\r\n  width:500px;\r\n  margin-bottom:8px;\r\n  font-size:21px;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-ionic-table th,\r\n.mcq-ionic-table td{\r\n  border:1.5px solid #c9ced8;\r\n  padding:12px 18px;\r\n  text-align:center;\r\n}\r\n\r\n.mcq-ionic-table th{\r\n  background:#f2f2f2;\r\n  font-weight:700;\r\n}\r\n\r\n.mcq-ionic-table td{\r\n  background:#eaf0ff;\r\n}\r\n\r\n.mcq-question-main{\r\n  margin:6px 0 28px;\r\n  font-size:24px;\r\n  line-height:1.35;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-options-wrap{\r\n  display:flex;\r\n  flex-direction:column;\r\n  gap:17px;\r\n  max-width:1200px;\r\n}\r\n\r\n.mcq-option-row{\r\n  display:flex;\r\n  align-items:center;\r\n  min-height:34px;\r\n  position:relative;\r\n}\r\n\r\n.mcq-radio{\r\n  width:28px;\r\n  height:28px;\r\n  border-radius:50%;\r\n  border:2px solid #6b7280;\r\n  margin-right:16px;\r\n  background:transparent;\r\n  position:relative;\r\n  flex:0 0 auto;\r\n}\r\n\r\n.mcq-radio::after{\r\n  content:\"\";\r\n  position:absolute;\r\n  inset:5px;\r\n  border-radius:50%;\r\n  background:#6b7280;\r\n  opacity:0;\r\n  transform:scale(0.4);\r\n  transition:opacity 0.25s ease,transform 0.25s ease;\r\n}\r\n\r\n.mcq-option-row.selected .mcq-radio::after{\r\n  opacity:1;\r\n  transform:scale(1);\r\n}\r\n\r\n.mcq-radio-ripple{\r\n  position:absolute;\r\n  left:14px;\r\n  top:50%;\r\n  width:28px;\r\n  height:28px;\r\n  border-radius:50%;\r\n  border:2px solid rgba(28,36,75,0.28);\r\n  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class=\"ols-mcq-scale-wrap\">\r\n        <main id=\"mcqScreen\" class=\"ols-mcq-screen\">\r\n          <section class=\"mcq-question-area\">\r\n            <p class=\"mcq-question-lead\">Some ionic radii are shown.<\/p>\r\n\r\n            <table class=\"mcq-ionic-table\">\r\n              <thead>\r\n                <tr>\r\n                  <th>Ion<\/th>\r\n                  <th>Ionic radius \/ nm<\/th>\r\n                <\/tr>\r\n              <\/thead>\r\n              <tbody>\r\n                <tr><td>Na<sup>+<\/sup><\/td><td>0.102<\/td><\/tr>\r\n                <tr><td>K<sup>+<\/sup><\/td><td>0.138<\/td><\/tr>\r\n                <tr><td>F<sup>\u2212<\/sup><\/td><td>0.133<\/td><\/tr>\r\n                <tr><td>Cl<sup>\u2212<\/sup><\/td><td>0.180<\/td><\/tr>\r\n              <\/tbody>\r\n            <\/table>\r\n\r\n            <p class=\"mcq-question-main\">Which compound has the strongest ionic bonding?<\/p>\r\n\r\n            <div class=\"mcq-options-wrap\">\r\n              <div id=\"mcqWrongOption\" class=\"mcq-option-row\">\r\n                <span class=\"mcq-radio\"><\/span>\r\n                <span class=\"mcq-radio-ripple\"><\/span>\r\n                <span class=\"mcq-option-label\">sodium chloride<\/span>\r\n\r\n                <span id=\"mcqSpecificFeedback\" class=\"mcq-specific-feedback\">\r\n                  <span id=\"mcqCrossIcon\" class=\"mcq-cross-icon\">\u00d7<\/span>\r\n                  <span class=\"mcq-specific-feedback-text\">\r\n                    <span id=\"mcqSpecificText\"><\/span><span id=\"mcqSpecificCursor\" class=\"cursor mcq-specific-cursor\" style=\"display:none;\"><\/span>\r\n                  <\/span>\r\n                <\/span>\r\n              <\/div>\r\n\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">potassium chloride<\/span><\/div>\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">sodium fluoride<\/span><\/div>\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">potassium fluoride<\/span><\/div>\r\n            <\/div>\r\n\r\n            <button id=\"mcqSubmitButton\" class=\"mcq-submit-button\">Submit answer<\/button>\r\n          <\/section>\r\n\r\n          <section id=\"mcqGeneralFeedback\" class=\"mcq-general-feedback\">\r\n            <span id=\"mcqGeneralText\"><\/span><span id=\"mcqGeneralCursor\" class=\"cursor mcq-general-cursor\" style=\"display:none;\"><\/span>\r\n          <\/section>\r\n        <\/main>\r\n      <\/div>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"sceneSaq\" class=\"ols-scene\">\r\n    <div class=\"ols-saq-stage\">\r\n      <div id=\"saqIntro\" class=\"ols-saq-intro\">\r\n        <div class=\"ols-saq-intro-title-wrap\">\r\n          <h1 class=\"ols-saq-intro-title\">\r\n            <span id=\"saqIntroTitleText\"><\/span><span id=\"saqIntroTitleCursor\" class=\"ols-title-cursor\"><\/span>\r\n          <\/h1>\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <div class=\"ols-saq-scale-wrap\">\r\n        <main id=\"saqScreen\" class=\"ols-saq-screen\">\r\n          <section class=\"saq-question-area\">\r\n            <div class=\"saq-question-text\">\r\n              <strong>(ii)<\/strong>&nbsp;&nbsp; Melting temperature depends on the strength of metallic bonding.<br>\r\n              Explain why the metallic bonding in magnesium is much stronger than that in sodium.\r\n            <\/div>\r\n\r\n            <div class=\"saq-student-box\">\r\n              <span id=\"saqStudentText\"><\/span><span id=\"saqStudentCursor\" class=\"cursor\"><\/span>\r\n            <\/div>\r\n          <\/section>\r\n\r\n          <section id=\"saqTeacherFeedback\" 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the ions can get closer together.\\n\"+\r\n\"\u2022 Smaller ions \u2192 stronger electrostatic attraction \u2192 stronger ionic lattice.\\n\"+\r\n\"\u2022 Na\u207a (0.102 nm) is smaller than K\u207a (0.138 nm).\\n\"+\r\n\"\u2022 F\u207b (0.133 nm) is smaller than Cl\u207b (0.180 nm).\\n\\n\"+\r\n\"Therefore, the strongest ionic bonding occurs in the compound formed by the smallest cation and the smallest anion \u2192 sodium fluoride (NaF).\\n\\n\"+\r\n\"The correct answer is: sodium fluoride\";\r\n\r\nconst mcqIntroScreen=document.getElementById(\"mcqIntroScreen\");\r\nconst mcqIntroTitleText=document.getElementById(\"mcqIntroTitleText\");\r\nconst mcqIntroTitleCursor=document.getElementById(\"mcqIntroTitleCursor\");\r\nconst mcqScreen=document.getElementById(\"mcqScreen\");\r\nconst mcqWrongOption=document.getElementById(\"mcqWrongOption\");\r\nconst mcqSubmitButton=document.getElementById(\"mcqSubmitButton\");\r\nconst 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Melting temperature is a result of bonding strength, not the cause of it.\\n\\n\"+\r\n\"In metallic bonding, positive metal ions are attracted to a sea of delocalised electrons. The strength of this attraction depends on the charge of the ions and the number of delocalised electrons.\\n\\n\"+\r\n\"Magnesium forms Mg\u00b2\u207a ions and contributes two delocalised electrons per atom, whereas sodium forms Na\u207a ions and contributes only one electron. This results in a stronger electrostatic attraction in magnesium. Additionally, Mg\u00b2\u207a ions have a higher charge density than Na\u207a ions, further strengthening the metallic bonding.\\n\\n\"+\r\n\"Next time, include:\\n\"+\r\n\"\u2022 Ion charge: magnesium forms Mg\u00b2\u207a, sodium forms Na\u207a \u2713\\n\"+\r\n\"\u2022 Delocalised electrons: magnesium provides more electrons to the sea \u2713\\n\"+\r\n\"\u2022 Charge density: smaller, more highly charged ions create stronger attraction \u2713\\n\\n\"+\r\n\"You were close. 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The bonding pairs repel equally and arrange themselves 120&deg; apart in one plane.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why is BCl<sub>3<\/sub> trigonal planar?<\/h3>\n            <p>BCl<sub>3<\/sub> has three B-Cl bonding pairs around the central boron atom and no lone pairs on boron in the shape model. The three bonding pairs repel equally, so the molecule is trigonal planar with 120&deg; bond angles.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>What is the bond angle in a trigonal planar molecule?<\/h3>\n            <p>The ideal bond angle in a trigonal planar molecule is 120&deg;.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Are all atoms in a trigonal planar molecule in one plane?<\/h3>\n            <p>Yes. In a trigonal planar molecule such as BCl<sub>3<\/sub>, the central atom and the three surrounding atoms lie in the same plane.<\/p>\n          <\/div>\n        <\/div>\n      <\/section>\n\n      <section class=\"ols-related-card\">\n        <h2>Related Topics<\/h2>\n        <p>Use these pages to connect trigonal planar shape with the wider bonding and structure topic.<\/p>\n        <div class=\"ols-related-grid\">\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/covalent-bonding\/\">Covalent Bonding<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/electronegativity\/\">Electronegativity<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/linear\/\">Linear<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/tetrahedral\/\">Tetrahedral<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/shapes-of-molecules\/bent\/\">Bent<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-3-chemical-bonding\/covalent-bonding\/polar-molecules\/\">Polar Molecules<\/a>\n        <\/div>\n      <\/section>\n      <section class=\"ols-attribution-card\">\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. 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