{"id":4577,"date":"2026-05-30T06:12:25","date_gmt":"2026-05-30T05:12:25","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/nature-of-ionic-bonding\/"},"modified":"2026-06-01T10:59:19","modified_gmt":"2026-06-01T09:59:19","slug":"nature-of-ionic-bonding","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/ionic-bonding\/nature-of-ionic-bonding\/","title":{"rendered":"Nature of Ionic Bonding"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-nature-of-ionic-bonding-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      --grey-text: #667085;\n      --body-text: 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grid-template-columns: 1fr; }\n      .ols-zoom-card { border-radius: 22px !important; overflow: hidden !important; }\n      .ols-zoom-card-image { min-height: 220px !important; padding: 16px !important; overflow: hidden !important; }\n      .ols-zoom-card img.ols-zoomable-img, .ols-zoom-card img.ols-zoomable-img:hover { transform: none !important; box-shadow: none !important; }\n      .ols-zoom-card-caption { padding: 16px !important; }\n      .ols-image-lightbox { padding: 16px; }\n      .ols-image-lightbox-inner { width: 100%; max-height: 88vh; }\n      .ols-image-lightbox-img { max-height: 88vh; border-radius: 16px; }\n      .ols-image-lightbox-close { top: 10px; right: 10px; width: 42px; height: 42px; font-size: 26px; }\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  <\/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>\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>\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      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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\/ionic-bonding\/\">Ionic Bonding<\/a> \/\n        <span>Nature of Ionic Bonding<\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Nature of Ionic Bonding<\/h1>\n        <p class=\"ols-page-intro\">A concise revision guide to ionic bonding, electron transfer, giant ionic lattice structure, ionic bonding strength and ionic radii for Edexcel A Level Chemistry.<\/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\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\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\n        View LinkedIn Profile\n\n      <\/a>\n\n    <\/div>\n\n  <\/div>\n      <\/header>\n\n      <article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>What Is Ionic Bonding?<\/h2>\n        <\/div>\n\n        <p><strong>Ionic bonding<\/strong> is the strong electrostatic force of attraction between oppositely charged ions formed by electron transfer.<\/p>\n        <p>In sodium chloride, a sodium atom transfers one electron to a chlorine atom. Sodium becomes a positive ion, <strong>Na<sup>+<\/sup><\/strong>, and chlorine becomes a negative ion, <strong>Cl<sup>&#8211;<\/sup><\/strong>.<\/p>\n        <p>The attraction between the <strong>Na<sup>+<\/sup><\/strong> cation and the <strong>Cl<sup>&#8211;<\/sup><\/strong> anion is an ionic bond.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> Ionic bonding is not the transfer of electrons itself. The bond is the electrostatic attraction between the oppositely charged ions after transfer has occurred.<\/p>\n        <\/div>\n\n        <div class=\"ols-zoom-card wide\">\n          <div class=\"ols-zoom-card-image\">\n            <img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Formation-of-Sodium-and-Chloride-Ions.webp\" alt=\"Formation of sodium and chloride ions by electron transfer\">\n          <\/div>\n          <div class=\"ols-zoom-card-caption\">\n            <p>Sodium loses one outer electron to form Na<sup>+<\/sup>, while chlorine gains one electron to form Cl<sup>&#8211;<\/sup>.<\/p>\n          <\/div>\n        <\/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>Giant Ionic Lattice Structure<\/h2>\n        <\/div>\n\n        <p>Ionic solids, such as sodium chloride, contain a <strong>giant ionic lattice<\/strong>. This means the ions are arranged in a repeating, ordered three-dimensional structure.<\/p>\n        <p>In sodium chloride, <strong>Na<sup>+<\/sup><\/strong> and <strong>Cl<sup>&#8211;<\/sup><\/strong> ions alternate in a regular pattern. Each ion is attracted to neighbouring ions with the opposite charge.<\/p>\n        <p>The electrostatic forces act in <strong>all possible directions<\/strong> through the lattice, so ionic bonding is not limited to one isolated pair of ions.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Term<\/th>\n                <th>Meaning<\/th>\n                <th>Exam focus<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Term\">Giant<\/td>\n                <td data-label=\"Meaning\">A very large repeating structure containing many ions.<\/td>\n                <td data-label=\"Exam focus\">Avoid describing NaCl as a small molecule.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Term\">Lattice<\/td>\n                <td data-label=\"Meaning\">A regular, repeating arrangement of particles.<\/td>\n                <td data-label=\"Exam focus\">Refer to a three-dimensional ionic lattice.<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Term\">Ionic bond<\/td>\n                <td data-label=\"Meaning\">Electrostatic attraction between oppositely charged ions.<\/td>\n                <td data-label=\"Exam focus\">Attractions act in all directions.<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-zoom-card wide\">\n          <div class=\"ols-zoom-card-image\">\n            <img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Ionic-Structure-of-Sodium-Chloride.webp\" alt=\"Giant ionic lattice structure of sodium chloride\">\n          <\/div>\n          <div class=\"ols-zoom-card-caption\">\n            <p>The alternating arrangement of Na<sup>+<\/sup> and Cl<sup>&#8211;<\/sup> ions produces a regular cubic lattice in sodium chloride.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n\n\n      <section class=\"ols-nacl-unitcell-section\" id=\"ols-nacl-unitcell-section\">\n  <style>\n    .ols-nacl-unitcell-section {\n      width: 100%;\n      padding: 32px 0;\n      font-family: Poppins, Arial, sans-serif;\n      color: #1C244B;\n    }\n\n    .ols-nacl-shell {\n      max-width: 1180px;\n      margin: 0 auto;\n      padding: 0 18px;\n    }\n\n    .ols-nacl-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      border: 1px solid rgba(28, 36, 75, 0.10);\n      border-radius: 28px;\n      box-shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      overflow: hidden;\n    }\n\n    .ols-nacl-header {\n      padding: 28px 28px 18px;\n      border-bottom: 1px solid rgba(28, 36, 75, 0.08);\n      background:\n        radial-gradient(circle at top left, rgba(201, 151, 58, 0.15), transparent 32%),\n        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gap: 22px;\n      align-items: stretch;\n    }\n\n    .ols-nacl-view-card {\n      background: #ffffff;\n      border: 1px solid rgba(28, 36, 75, 0.10);\n      border-radius: 24px;\n      box-shadow: 0 12px 28px rgba(28, 36, 75, 0.08);\n      padding: 16px;\n      min-width: 0;\n    }\n\n    .ols-nacl-viewer {\n      width: 100%;\n      height: 560px;\n      min-height: 460px;\n      border-radius: 20px;\n      background:\n        linear-gradient(135deg, rgba(238, 244, 255, 0.85), rgba(255, 255, 255, 0.96)),\n        radial-gradient(circle at center, rgba(28, 36, 75, 0.08), transparent 55%);\n      border: 1px solid rgba(28, 36, 75, 0.08);\n      overflow: hidden;\n      position: relative;\n    }\n\n    .ols-nacl-control-panel {\n      margin-top: 14px;\n      display: flex;\n      flex-wrap: wrap;\n      gap: 10px;\n      justify-content: center;\n      align-items: center;\n    }\n\n    .ols-nacl-btn {\n      appearance: none;\n      border: 1px solid rgba(28, 36, 75, 0.16);\n      background: #ffffff;\n      color: #1C244B;\n      border-radius: 999px;\n      padding: 10px 14px;\n      font-family: Poppins, Arial, sans-serif;\n      font-size: 13px;\n      font-weight: 700;\n      cursor: pointer;\n      box-shadow: 0 6px 16px rgba(28, 36, 75, 0.08);\n      transition: transform 0.22s ease, box-shadow 0.22s ease, background 0.22s ease, color 0.22s ease;\n    }\n\n    .ols-nacl-btn:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.14);\n      background: #1C244B;\n      color: #ffffff;\n    }\n\n    .ols-nacl-btn.is-active {\n      background: #1C244B;\n      color: #ffffff;\n      border-color: #1C244B;\n    }\n\n    .ols-nacl-info-card {\n      background: #ffffff;\n      border: 1px solid rgba(28, 36, 75, 0.10);\n      border-radius: 24px;\n      box-shadow: 0 12px 28px rgba(28, 36, 75, 0.08);\n      padding: 22px;\n    }\n\n    .ols-nacl-info-title {\n      margin: 0 0 12px;\n      font-size: 22px;\n      line-height: 1.2;\n      font-weight: 700;\n      color: #1C244B;\n    }\n\n    .ols-nacl-info-text {\n      margin: 0 0 18px;\n      font-size: 15px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: rgba(28, 36, 75, 0.84);\n    }\n\n    .ols-nacl-pill-row {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 9px;\n      margin: 0 0 18px;\n    }\n\n    .ols-nacl-pill {\n      display: inline-flex;\n      align-items: center;\n      gap: 8px;\n      border-radius: 999px;\n      padding: 8px 12px;\n      font-size: 13px;\n      line-height: 1;\n      font-weight: 700;\n      border: 1px solid rgba(28, 36, 75, 0.12);\n      background: #f7f8fb;\n      color: #1C244B;\n    }\n\n    .ols-nacl-dot {\n      width: 11px;\n      height: 11px;\n      border-radius: 50%;\n      display: inline-block;\n      flex: 0 0 auto;\n    }\n\n    .ols-nacl-dot-na {\n      background: #7c5cff;\n      box-shadow: 0 0 0 4px rgba(124, 92, 255, 0.13);\n    }\n\n    .ols-nacl-dot-cl {\n      background: #42b883;\n      box-shadow: 0 0 0 4px rgba(66, 184, 131, 0.14);\n    }\n\n    .ols-nacl-dot-bond {\n      background: #fff200;\n      box-shadow: 0 0 0 4px rgba(255, 242, 0, 0.22);\n    }\n\n    .ols-nacl-key-list {\n      list-style: none;\n      padding: 0;\n      margin: 0;\n      display: grid;\n      gap: 12px;\n    }\n\n    .ols-nacl-key-list li {\n      padding: 13px 14px;\n      border-radius: 16px;\n      background: #f8fbff;\n      border: 1px solid rgba(28, 36, 75, 0.08);\n      font-size: 14px;\n      line-height: 1.55;\n      color: rgba(28, 36, 75, 0.86);\n      font-weight: 300;\n    }\n\n    .ols-nacl-key-list strong {\n      color: #1C244B;\n      font-weight: 700;\n    }\n\n    .ols-nacl-bottom-note {\n      margin-top: 20px;\n      padding: 16px 18px;\n      border-radius: 18px;\n      background: rgba(201, 151, 58, 0.12);\n      border: 1px solid rgba(201, 151, 58, 0.22);\n      color: #5e4316;\n      font-size: 14px;\n      line-height: 1.65;\n      font-weight: 400;\n    }\n\n    @media (max-width: 980px) {\n      .ols-nacl-body {\n        grid-template-columns: 1fr;\n      }\n\n      .ols-nacl-viewer {\n        height: 520px;\n      }\n    }\n\n    @media (max-width: 620px) {\n      .ols-nacl-header {\n        padding: 24px 20px 16px;\n      }\n\n      .ols-nacl-body {\n        padding: 16px;\n      }\n\n      .ols-nacl-view-card,\n      .ols-nacl-info-card {\n        border-radius: 20px;\n        padding: 14px;\n      }\n\n      .ols-nacl-viewer {\n        height: 430px;\n        min-height: 380px;\n        border-radius: 16px;\n      }\n\n      .ols-nacl-subtitle {\n        font-size: 16px;\n      }\n\n      .ols-nacl-btn {\n        width: 100%;\n        justify-content: center;\n      }\n    }\n  <\/style>\n\n  <div class=\"ols-nacl-shell\">\n    <div class=\"ols-nacl-card\">\n      <div class=\"ols-nacl-header\">\n        <div class=\"ols-nacl-kicker\">3D ionic lattice model<\/div>\n        <h2 class=\"ols-nacl-title\">Sodium chloride: one repeat unit cell<\/h2>\n        <p class=\"ols-nacl-subtitle\">\n          This interactive model shows the rock-salt arrangement of sodium chloride. The central Na<sup>+<\/sup> ion is highlighted with its six nearest Cl<sup>\u2212<\/sup> neighbours in the x, y and z directions.\n        <\/p>\n      <\/div>\n\n      <div class=\"ols-nacl-body\">\n        <div class=\"ols-nacl-view-card\">\n          <div id=\"olsNaClViewer01\" class=\"ols-nacl-viewer\"><\/div>\n\n          <div class=\"ols-nacl-control-panel\" aria-label=\"Sodium chloride model controls\">\n            <button class=\"ols-nacl-btn is-active\" id=\"olsNaClRotateBtn01\" type=\"button\">Pause rotation<\/button>\n            <button class=\"ols-nacl-btn is-active\" id=\"olsNaClBondsBtn01\" type=\"button\">Hide 6 ionic links<\/button>\n            <button class=\"ols-nacl-btn is-active\" id=\"olsNaClCellBtn01\" type=\"button\">Hide unit cell<\/button>\n            <button class=\"ols-nacl-btn is-active\" id=\"olsNaClLabelsBtn01\" type=\"button\">Hide labels<\/button>\n            <button class=\"ols-nacl-btn\" id=\"olsNaClResetBtn01\" type=\"button\">Reset view<\/button>\n          <\/div>\n        <\/div>\n\n        <aside class=\"ols-nacl-info-card\">\n          <h3 class=\"ols-nacl-info-title\">What the model shows<\/h3>\n\n          <div class=\"ols-nacl-pill-row\">\n            <span class=\"ols-nacl-pill\"><span class=\"ols-nacl-dot ols-nacl-dot-na\"><\/span>Na<sup>+<\/sup> ion<\/span>\n            <span class=\"ols-nacl-pill\"><span class=\"ols-nacl-dot ols-nacl-dot-cl\"><\/span>Cl<sup>\u2212<\/sup> ion<\/span>\n            <span class=\"ols-nacl-pill\"><span class=\"ols-nacl-dot ols-nacl-dot-bond\"><\/span>Nearest-neighbour attraction<\/span>\n          <\/div>\n\n          <p class=\"ols-nacl-info-text\">\n            Sodium chloride forms a giant ionic lattice. Each Na<sup>+<\/sup> ion is surrounded by six Cl<sup>\u2212<\/sup> ions, and each Cl<sup>\u2212<\/sup> ion is surrounded by six Na<sup>+<\/sup> ions.\n          <\/p>\n\n          <ul class=\"ols-nacl-key-list\">\n            <li><strong>Central ion:<\/strong> the highlighted Na<sup>+<\/sup> ion is placed at the centre of the unit cell.<\/li>\n            <li><strong>Six-coordinate:<\/strong> six Cl<sup>\u2212<\/sup> ions surround it along +x, \u2212x, +y, \u2212y, +z and \u2212z.<\/li>\n            <li><strong>Giant structure:<\/strong> the same pattern repeats in all three dimensions.<\/li>\n            <li><strong>Strong ionic bonding:<\/strong> oppositely charged ions are held together by electrostatic attraction.<\/li>\n          <\/ul>\n\n          <div class=\"ols-nacl-bottom-note\">\n            Drag to rotate the lattice. Scroll or pinch to zoom. The bright yellow connectors are not covalent bonds; they mark the six nearest oppositely charged ions around the selected ion.\n          <\/div>\n        <\/aside>\n      <\/div>\n    <\/div>\n  <\/div>\n\n  <script src=\"https:\/\/cdnjs.cloudflare.com\/ajax\/libs\/three.js\/r128\/three.min.js\"><\/script>\n  <script src=\"https:\/\/cdn.jsdelivr.net\/npm\/three@0.128.0\/examples\/js\/controls\/OrbitControls.min.js\"><\/script>\n  <script src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/JS\/NaCl.js\"><\/script>\n<\/section>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>Ionic Bonding Strength<\/h2>\n        <\/div>\n\n        <p>Ionic bonds become stronger when the ions are <strong>smaller<\/strong> and\/or carry <strong>greater charges<\/strong>.<\/p>\n        <p>Smaller ions allow oppositely charged ions to get closer together, increasing electrostatic attraction. Higher ionic charges also increase the attraction between ions.<\/p>\n        <p>This is why magnesium oxide, <strong>MgO<\/strong>, has a much higher melting temperature than sodium chloride, <strong>NaCl<\/strong>. The ions in MgO, <strong>Mg<sup>2+<\/sup><\/strong> and <strong>O<sup>2-<\/sup><\/strong>, are smaller and more highly charged than <strong>Na<sup>+<\/sup><\/strong> and <strong>Cl<sup>&#8211;<\/sup><\/strong>.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Compound<\/th>\n                <th>Ions involved<\/th>\n                <th>Ion size<\/th>\n                <th>Ion charge<\/th>\n                <th>Relative melting point<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Compound\"><strong>NaCl<\/strong><\/td>\n                <td data-label=\"Ions involved\">Na<sup>+<\/sup> and Cl<sup>&#8211;<\/sup><\/td>\n                <td data-label=\"Ion size\">Larger<\/td>\n                <td data-label=\"Ion charge\">\u00b11<\/td>\n                <td data-label=\"Relative melting point\">801 \u00b0C<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Compound\"><strong>MgO<\/strong><\/td>\n                <td data-label=\"Ions involved\">Mg<sup>2+<\/sup> and O<sup>2-<\/sup><\/td>\n                <td data-label=\"Ion size\">Smaller<\/td>\n                <td data-label=\"Ion charge\">\u00b12<\/td>\n                <td data-label=\"Relative melting point\">2852 \u00b0C<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam focus:<\/strong> When comparing ionic bonding strength, refer to both <strong>charge<\/strong> and <strong>ionic radius<\/strong> where relevant.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card orange\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">4<\/div>\n          <h2>Ionic Radii<\/h2>\n        <\/div>\n\n        <p><strong>Positive ions<\/strong>, called cations, are smaller than their parent atoms. This is often because an entire outer electron shell is lost and the remaining electrons are pulled in more strongly by the nucleus.<\/p>\n        <p><strong>Negative ions<\/strong>, called anions, are larger than their parent atoms. Extra electrons are added while the number of protons stays the same, so the nuclear attraction is spread over more electrons.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Ion<\/th>\n                <th>Li<sup>+<\/sup><\/th>\n                <th>Na<sup>+<\/sup><\/th>\n                <th>K<sup>+<\/sup><\/th>\n                <th>Rb<sup>+<\/sup><\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Ion\"><strong>Ionic radius \/ nm<\/strong><\/td>\n                <td data-label=\"Li+\">0.060<\/td>\n                <td data-label=\"Na+\">0.095<\/td>\n                <td data-label=\"K+\">0.133<\/td>\n                <td data-label=\"Rb+\">0.148<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Ion<\/th>\n                <th>N<sup>3-<\/sup><\/th>\n                <th>O<sup>2-<\/sup><\/th>\n                <th>F<sup>&#8211;<\/sup><\/th>\n                <th>Na<sup>+<\/sup><\/th>\n                <th>Mg<sup>2+<\/sup><\/th>\n                <th>Al<sup>3+<\/sup><\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td data-label=\"Ion\"><strong>No. of electrons<\/strong><\/td>\n                <td data-label=\"N3-\">10<\/td>\n                <td data-label=\"O2-\">10<\/td>\n                <td data-label=\"F-\">10<\/td>\n                <td data-label=\"Na+\">10<\/td>\n                <td data-label=\"Mg2+\">10<\/td>\n                <td data-label=\"Al3+\">10<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Ion\"><strong>No. of protons<\/strong><\/td>\n                <td data-label=\"N3-\">7<\/td>\n                <td data-label=\"O2-\">8<\/td>\n                <td data-label=\"F-\">9<\/td>\n                <td data-label=\"Na+\">11<\/td>\n                <td data-label=\"Mg2+\">12<\/td>\n                <td data-label=\"Al3+\">13<\/td>\n              <\/tr>\n              <tr>\n                <td data-label=\"Ion\"><strong>Ionic radius \/ nm<\/strong><\/td>\n                <td data-label=\"N3-\">0.171<\/td>\n                <td data-label=\"O2-\">0.140<\/td>\n                <td data-label=\"F-\">0.136<\/td>\n                <td data-label=\"Na+\">0.095<\/td>\n                <td data-label=\"Mg2+\">0.065<\/td>\n                <td data-label=\"Al3+\">0.050<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> In an isoelectronic series, the ions have the same number of electrons. As the number of protons increases, the attraction for those electrons increases and the ionic radius decreases.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">5<\/div>\n          <h2>Common Exam Points<\/h2>\n        <\/div>\n\n        <p>For ionic bonding and structure questions, exam answers usually need precise language. The most important phrases are <strong>oppositely charged ions<\/strong>, <strong>strong electrostatic attraction<\/strong>, <strong>giant ionic lattice<\/strong> and <strong>attraction in all directions<\/strong>.<\/p>\n\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>Do not call ionic compounds molecules<\/h3>\n            <p>NaCl is normally described as a giant ionic lattice, not as individual NaCl molecules.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Separate electron transfer from bonding<\/h3>\n            <p>Electron transfer forms ions. The ionic bond is the electrostatic attraction between those ions.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Use charge and radius in explanations<\/h3>\n            <p>Greater charge and smaller ionic radius generally produce stronger ionic attractions and higher melting temperatures.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <section class=\"ols-h5p-card\">\n        <h2>Check Your Understanding<\/h2>\n        <p>Use these short activities to check ionic bonding, electron transfer, lattice structure, ionic bonding strength and ionic radii before moving on.<\/p>\n\n        <div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-152\" class=\"h5p-iframe\" data-content-id=\"152\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"T3.1.1.1 Drag: Ionic Bonding Key Concepts\"><\/iframe><\/div><\/div>\n        <div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-153\" class=\"h5p-iframe\" data-content-id=\"153\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"T3.1.1.2 MCQ: Formation of Sodium Chloride Ions\"><\/iframe><\/div><\/div>\n        <div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-154\" class=\"h5p-iframe\" data-content-id=\"154\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"T3.1.1.3 MCQ: Giant Ionic Lattice Structure\"><\/iframe><\/div><\/div>\n        <div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-155\" class=\"h5p-iframe\" data-content-id=\"155\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"T3.1.1.4 MCQ: Ionic Bonding Strength\"><\/iframe><\/div><\/div>\n      <\/section>\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\n        <p>For this page, the essential idea is that <strong>electron transfer forms ions<\/strong>, but the <strong>ionic bond<\/strong> is the strong electrostatic attraction between those oppositely charged ions.<\/p>\n\n        <div class=\"ols-rule-list\">\n          <div class=\"ols-rule-item\">\n            <h3>Formation of ions<\/h3>\n            <p>Metals lose electrons to form positive cations, while non-metals gain electrons to form negative anions. For example, sodium forms Na<sup>+<\/sup> and chlorine forms Cl<sup>&#8211;<\/sup>.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Giant ionic lattice<\/h3>\n            <p>Ionic compounds form regular, repeating three-dimensional lattices. The attractions act in all directions between neighbouring oppositely charged ions.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Bond strength<\/h3>\n            <p>Ionic bonding is stronger when ions are smaller and\/or more highly charged. This explains why MgO has a much higher melting point than NaCl.<\/p>\n          <\/div>\n          <div class=\"ols-rule-item\">\n            <h3>Ionic radius<\/h3>\n            <p>Cations are smaller than their parent atoms because electrons are lost. 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inline-flex;\r\n      align-items: 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-ionic-metallic .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-ionic-metallic .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-ionic-metallic .ols-course-cta-top {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-image-link {\r\n        max-width: 520px;\r\n        margin: 0 auto;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-intro-stats {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .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-ionic-metallic {\r\n        margin: 26px 0 22px;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-card {\r\n        padding: 20px;\r\n        border-radius: 24px;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-header-row {\r\n        align-items: stretch;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-button-top {\r\n        width: 100%;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-stats,\r\n      .ols-course-cta-ionic-metallic .ols-course-cta-features {\r\n        grid-template-columns: 1fr;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-course-animation-wrap {\r\n        padding: 0;\r\n        border-radius: 0;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-animation-frame-shell {\r\n        height: 420px;\r\n        border-radius: 18px;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .ols-animation-play-circle {\r\n        width: 76px;\r\n        height: 76px;\r\n      }\r\n\r\n      .ols-course-cta-ionic-metallic .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-ionic-metallic .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-ionic-metallic .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\/metallic-bonding-edexcel-a-level-chemistry\/\" aria-label=\"Open the Edexcel A Level Chemistry Topic 2A\/B Ionic and Metallic Bonding 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\/05\/T2AB-Course-Card.jpg\"\r\n            alt=\"Edexcel A Level Chemistry Topic 2A\/B Ionic and Metallic Bonding course card\"\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            Complete Topic 2A\/B Ionic & Metallic Bonding Course\r\n          <\/div>\r\n\r\n          <a class=\"ols-course-button ols-course-button-top\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/metallic-bonding-edexcel-a-level-chemistry\/\">\r\n            View Course\r\n          <\/a>\r\n\r\n        <\/div>\r\n\r\n        <h2>\r\n          Master Ionic Bonding and Metallic Bonding for Edexcel 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 2A\/B Ionic and Metallic Bonding course, with guided video teaching, diagnostic MCQ practice, teacher-marked short-answer questions and a specification assignment with a personalised progress report.\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>Guided learning<\/span>\r\n          <strong>11 hours<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>Video lessons<\/span>\r\n          <strong>288 mins<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>MCQ practice<\/span>\r\n          <strong>51 marks<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>SAQ practice<\/span>\r\n          <strong>68 marks<\/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 ions, ionic lattices, polarisation and metallic bonding 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 ions, ionic bonding, ionic radii, polarisation and metallic bonding 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\/metallic-bonding-edexcel-a-level-chemistry\/\">\r\n        View Ionic & Metallic Bonding Topic 2A\/B 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  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}\r\n}\r\n<\/style>\r\n<\/head>\r\n\r\n<body>\r\n<div class=\"ols-combined-stage\">\r\n\r\n  <section id=\"sceneVideo\" class=\"ols-scene active\">\r\n    <div class=\"ols-video-stage\">\r\n      <div id=\"videoTitleScreen\" class=\"ols-video-title-screen\">\r\n        <div class=\"ols-video-title-wrap\">\r\n          <h1 class=\"ols-video-title\">\r\n            <span id=\"videoTitleText\"><\/span><span id=\"videoTitleCursor\" class=\"ols-title-cursor\"><\/span>\r\n          <\/h1>\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <section id=\"videoScene\" class=\"ols-video-scene\">\r\n        <div class=\"ols-video-scale-wrap\">\r\n          <div class=\"ols-video-card\">\r\n            <video\r\n              id=\"lessonVideo\"\r\n              src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Virtual-Lesson.mp4\"\r\n              muted\r\n              playsinline\r\n              preload=\"auto\">\r\n            <\/video>\r\n          <\/div>\r\n        <\/div>\r\n      <\/section>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"sceneMcq\" class=\"ols-scene\">\r\n    <div class=\"ols-mcq-stage\">\r\n      <div id=\"mcqIntroScreen\" class=\"ols-mcq-intro-screen\">\r\n        <div class=\"ols-mcq-intro-title-wrap\">\r\n          <h1 class=\"ols-mcq-intro-title\">\r\n            <span id=\"mcqIntroTitleText\"><\/span><span id=\"mcqIntroTitleCursor\" class=\"ols-title-cursor\"><\/span>\r\n          <\/h1>\r\n        <\/div>\r\n      <\/div>\r\n\r\n      <div 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\" class=\"saq-teacher-feedback\">\r\n            <span id=\"saqTeacherText\"><\/span><span id=\"saqTeacherCursor\" class=\"cursor saq-teacher-cursor\" style=\"display:none;\"><\/span>\r\n          <\/section>\r\n        <\/main>\r\n      <\/div>\r\n    <\/div>\r\n  <\/section>\r\n\r\n<\/div>\r\n\r\n<script>\r\n(function(){\r\n  const nativeSetTimeout=window.setTimeout.bind(window);\r\n  const nativeClearTimeout=window.clearTimeout.bind(window);\r\n  let nextTimerId=1;\r\n  let paused=false;\r\n  const 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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 ionic bond is the electrostatic attraction between those oppositely charged ions.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>What is a giant ionic lattice?<\/h3>\n            <p>A giant ionic lattice is a regular, repeating three-dimensional arrangement of ions held together by electrostatic attractions in all directions.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Why does MgO have a higher melting point than NaCl?<\/h3>\n            <p>MgO contains Mg<sup>2+<\/sup> and O<sup>2-<\/sup> ions, which are more highly charged and smaller than Na<sup>+<\/sup> and Cl<sup>&#8211;<\/sup> ions. This creates stronger electrostatic attractions, so more energy is needed to melt MgO.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Why are cations smaller than their parent atoms?<\/h3>\n            <p>Cations are smaller because electrons are lost. Often an entire electron shell is removed, and the remaining electrons experience a stronger attraction from the nucleus.<\/p>\n          <\/div>\n\n          <div class=\"ols-faq-item\">\n            <h3>Why are anions larger than their parent atoms?<\/h3>\n            <p>Anions are larger because extra electrons are added while the number of protons stays the same. The nuclear attraction is spread over more electrons, so the outer electrons are held less tightly.<\/p>\n          <\/div>\n        <\/div>\n      <\/section>\n\n      <section class=\"ols-related-card\">\n        <h2>Related Ionic Bonding Revision Notes<\/h2>\n        <p>Continue through Topic 2 by linking ionic bonding to polarisation, ionic properties and covalent bonding.<\/p>\n\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\/ionic-bonding\/polarisation-of-ions\/\">Polarisation of Ions<\/a>\n          <a class=\"ols-related-item\" 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>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-2-bonding-and-structure\/covalent-bonding\/\">Covalent Bonding<\/a>\n        <\/div>\n      <\/section>\n\n    \n\n      <section class=\"ols-attribution-card\">\n  <style>\n    .ols-attribution-card {\n      background: linear-gradient(135deg, #ffffff, #f8fbff);\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: 34px;\n      margin-bottom: 24px;\n      overflow: hidden;\n      font-family: Poppins, Arial, sans-serif;\n      box-sizing: border-box;\n    }\n\n    .ols-attribution-card,\n    .ols-attribution-card * {\n      box-sizing: border-box;\n    }\n\n    .ols-attribution-card p {\n      margin: 0;\n      font-size: 14px;\n      line-height: 1.65;\n      font-weight: 300;\n      color: #667085;\n    }\n\n    .ols-attribution-card strong {\n      font-weight: 700;\n      color: #1C244B;\n    }\n\n    @media (max-width: 760px) {\n      .ols-attribution-card {\n        padding: 24px 18px;\n        border-radius: 22px;\n      }\n    }\n  <\/style>\n\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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