{"id":5340,"date":"2026-06-24T09:18:33","date_gmt":"2026-06-24T08:18:33","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/giant-covalent-structures\/"},"modified":"2026-09-20T09:40:26","modified_gmt":"2026-09-20T08:40:26","slug":"giant-covalent-structures","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/giant-covalent-structures\/","title":{"rendered":"Giant Covalent Structures"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-nature-of-covalent-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: #1f2937;\n      --border: rgba(28, 36, 75, 0.14);\n      --shadow: 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.ols-figure-placeholder .ols-figure-caption p { margin: 10px 0 0; font-size: 14px; color: #667085; text-align: center; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>AQA A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>3.1.3 Bonding<\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/ionic-bonding\/physical-properties-of-ionic-compounds\/\">Physical Properties of Ionic Compounds<\/a>\r\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/ionic-bonding\/ions-and-ionic-formulae\/\">Ions and Ionic Formulae<\/a>\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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/covalent-bonding\/covalent-bonding\/\">Covalent Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/\">Shapes of Molecules and Ions<\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/linear\/\">Linear<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/tetrahedral\/\">Tetrahedral<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/bent\/\">Bent<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/octahedral\/\">Octahedral<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/shapes-of-molecules-and-ions\/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\/aqa\/3-1-3-bonding\/bond-polarity\/\">Bond Polarity<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/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\/aqa\/3-1-3-bonding\/giant-covalent-structures\/\">Giant Covalent Structures<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/simple-molecular-structures\/\">Simple Molecular Structures<\/a>\r\n      <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/structure-types\/\">Structure Types<\/a>\n          <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/\">Intermolecular Forces<\/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\/aqa\/3-1-3-bonding\/intermolecular-forces\/london-forces\/\">London Forces<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/permanent-dipole-dipole-forces\/\">Permanent Dipole-Dipole Forces<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/hydrogen-bonding\/\">Hydrogen Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/anomalous-properties-of-water\/\">Anomalous Properties of Water<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/boiling-temperature-trends\/\">Boiling Point Trends<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/intermolecular-forces\/choosing-solvents\/\">Choosing Solvents<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Adjacent 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\/aqa\/3-1-1-atomicstructure\/\">3.1.1 Atomic Structure<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/\">3.1.2 Amount of Substance<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-4-energetics\/\">3.1.4 Energetics<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-2-1-periodicity\/\">3.2.1 Periodicity<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      .replace(\/\\\/+$\/, '')\r\n      .toLowerCase();\r\n  }\r\n\r\n  function highlightActive() {\r\n    var sidebar = document.querySelector('.ols-sidebar');\r\n    if (!sidebar) return false;\r\n\r\n    var currentPath = normalisePath(window.location.pathname);\r\n    var links = sidebar.querySelectorAll('a[href]');\r\n    var matched = null;\r\n    var matchedLength = 0;\r\n\r\n    sidebar.querySelectorAll('.active, .active-main, .parent-active').forEach(function(item) {\r\n      item.classList.remove('active', 'active-main', 'parent-active');\r\n    });\r\n\r\n    sidebar.querySelectorAll('a[data-ols-disabled-parent=\"1\"], 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true;\r\n  }\r\n\r\n  if (!highlightActive()) {\r\n    document.addEventListener('DOMContentLoaded', highlightActive);\r\n  }\r\n})();\r\n<\/script>\n\n  <main class=\"ols-main\">\n      <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/\">AQA<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/\">3.1.3 Bonding<\/a> \/\n<span>Giant Covalent Structures<\/span>\n<\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Giant Covalent Structures<\/h1>\n        <p class=\"ols-page-intro\">A concise revision guide to giant covalent structures: how diamond, graphite and graphene are bonded, why their properties differ so much, and how the structure explains melting point, hardness and electrical conductivity.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Paper 1 and 2<\/div>\n<div class=\"ols-badge\">AQA<\/div>\n<div class=\"ols-badge\">3.1.3 Bonding<\/div>\n<div class=\"ols-badge\">7405\/1 and 7405\/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:<br><span>Dr. Mohammed Al-Fatah<\/span>\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      <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: Covalent Bonds and Small Molecules<\/h2>\n<p>Before you start, check three GCSE ideas that this page builds on.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"657\"><\/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 Is a Giant Covalent Structure?<\/h2>\n<\/div>\n<p>In a <strong>giant covalent structure<\/strong> (also called a macromolecular or giant molecular structure) every atom is joined to its neighbours by <strong>strong covalent bonds<\/strong> that extend throughout the whole crystal. There are no separate molecules: a single crystal of diamond is, in effect, one enormous molecule. Compare this with a simple molecular substance such as iodine, where strong covalent bonds hold each I<sub>2<\/sub> molecule together but only weak intermolecular forces act between the molecules.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Feature<\/th><th>Giant covalent (diamond, graphite, graphene)<\/th><th>Simple molecular (iodine, ice, carbon dioxide)<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Particles<\/strong><\/td><td>Atoms in a continuous network<\/td><td>Discrete molecules<\/td><\/tr>\n<tr><td><strong>Forces broken on melting<\/strong><\/td><td>Strong covalent bonds<\/td><td>Weak intermolecular forces<\/td><\/tr>\n<tr><td><strong>Melting point<\/strong><\/td><td>Very high (diamond sublimes above 3600 \u00b0C)<\/td><td>Low<\/td><\/tr>\n<tr><td><strong>Solubility in water<\/strong><\/td><td>Insoluble<\/td><td>Usually low; some polar molecules dissolve<\/td><\/tr>\n<tr><td><strong>Electrical conductivity<\/strong><\/td><td>Usually none; graphite and graphene conduct<\/td><td>None<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Key idea:<\/strong> Melting a giant covalent structure means breaking covalent bonds, which needs a great deal of energy, so these substances have very high melting points and are hard or, in the case of graphite, strongly bonded within each layer.<\/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: Identify the Structure from Data<\/h2>\n<p>Use the data to decide which type of structure the solid has.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-440\" class=\"h5p-iframe\" data-content-id=\"440\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures MCQ: Identifying the Structure from Data\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">2<\/div>\n<h2>Diamond<\/h2>\n<\/div>\n<p>In <strong>diamond<\/strong> each carbon atom forms <strong>four single covalent bonds<\/strong> to four other carbon atoms arranged <strong>tetrahedrally<\/strong> around it, with bond angles of 109.5\u00b0. The result is a rigid three-dimensional network in which every atom is locked in place by strong C-C bonds.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Property<\/th><th>Explanation from the structure<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Very high melting and sublimation point<\/strong><\/td><td>Many strong covalent bonds must be broken<\/td><\/tr>\n<tr><td><strong>Extremely hard<\/strong><\/td><td>The rigid tetrahedral network resists any distortion; diamond is used in cutting tools and drill tips<\/td><\/tr>\n<tr><td><strong>Does not conduct electricity<\/strong><\/td><td>All four outer electrons of each carbon are used in bonding, so there are no delocalised electrons<\/td><\/tr>\n<tr><td><strong>Insoluble in all solvents<\/strong><\/td><td>No solvent interaction can compete with the covalent bonds<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-zoom-card\">\n<div class=\"ols-zoom-card-image\">\n<a class=\"ols-lightbox-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/fragment-of-the-diamond-lattice.jpg\" aria-label=\"Open image full screen\">\n<img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/fragment-of-the-diamond-lattice.jpg\" alt=\"Fragment of the diamond lattice: every carbon atom bonded tetrahedrally to four others\">\n<\/a>\n<\/div>\n<div class=\"ols-zoom-card-caption\"><p>Diamond: every carbon atom is bonded tetrahedrally to four others in a rigid three-dimensional network.<\/p><\/div>\n<\/div>\n<p><strong>Silicon<\/strong> has the same structure as diamond, which is why it is also a hard, high-melting solid, although its Si-Si bonds are weaker than C-C bonds.<\/p>\n<div class=\"ols-key-box\">\n<p><strong>Exam sentence:<\/strong> Diamond has a giant covalent structure in which each carbon atom is bonded to four others by strong covalent bonds, so a large amount of energy is needed to break the bonds and it has a very high melting point.<\/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: Predict the Properties of Silicon Carbide<\/h2>\n<p>Use the structure described to predict the properties of a compound you have not met on this page.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-438\" class=\"h5p-iframe\" data-content-id=\"438\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures MCQ: Silicon Carbide\"><\/iframe><\/div><\/div>\n<\/section>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Explain Silicon and Phosphorus<\/h2>\n<p>Write a short explanation, 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-658\" class=\"h5p-iframe\" data-content-id=\"658\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures Explain: Melting Temperatures of Silicon and White Phosphorus\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card purple\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">3<\/div>\n<h2>Graphite<\/h2>\n<\/div>\n<p>In <strong>graphite<\/strong> each carbon atom forms <strong>three covalent bonds<\/strong> to three other carbon atoms, giving flat <strong>hexagonal layers<\/strong> with bond angles of 120\u00b0. The fourth outer electron of each carbon is not used in a localised bond; it sits in a p orbital above and below the layer and becomes <strong>delocalised<\/strong> across the whole sheet. The layers are held to each other only by <strong>weak intermolecular forces<\/strong> (induced dipole-dipole or van der Waals forces), and are relatively far apart.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Property<\/th><th>Explanation from the structure<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Very high melting point<\/strong><\/td><td>The strong covalent bonds within the layers must be broken<\/td><\/tr>\n<tr><td><strong>Soft and slippery<\/strong><\/td><td>The weak forces between layers let them slide over each other; graphite is used as a lubricant and in pencils<\/td><\/tr>\n<tr><td><strong>Conducts electricity<\/strong><\/td><td>The delocalised electrons can move along the layers when a voltage is applied<\/td><\/tr>\n<tr><td><strong>Low density compared with diamond<\/strong><\/td><td>The layers are widely spaced<\/td><\/tr>\n<tr><td><strong>Insoluble<\/strong><\/td><td>Covalent bonding throughout the layers<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-zoom-card\">\n<div class=\"ols-zoom-card-image\">\n<a class=\"ols-lightbox-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/three-stacked-hexagonal-layers-of-graphite.jpg\" aria-label=\"Open image full screen\">\n<img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/three-stacked-hexagonal-layers-of-graphite.jpg\" alt=\"Three stacked hexagonal layers of graphite held together by weak forces between the layers\">\n<\/a>\n<\/div>\n<div class=\"ols-zoom-card-caption\"><p>Graphite: strong covalent bonds within hexagonal layers, weak forces between them, and delocalised electrons that conduct electricity.<\/p><\/div>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Exam focus:<\/strong> Graphite conducts because it has delocalised electrons; it is soft because the layers are held together only by weak intermolecular forces. Do not say the layers are held by covalent bonds, and do not say graphite conducts because it is a metal.<\/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: Which Way Does Graphite Conduct?<\/h2>\n<p>Predict what happens when the conductivity of a graphite crystal is measured in two directions.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-439\" class=\"h5p-iframe\" data-content-id=\"439\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures MCQ: Conductivity of Graphite in Two Directions\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">4<\/div>\n<h2>Graphene<\/h2>\n<\/div>\n<p><strong>Graphene<\/strong> is a <strong>single layer of graphite<\/strong>: a sheet of carbon atoms one atom thick, each bonded covalently to three others in a hexagonal pattern, with one delocalised electron per carbon spread over the sheet. It is described as a two-dimensional giant covalent structure.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Property<\/th><th>Explanation<\/th><th>Application<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Extremely strong for its thickness<\/strong><\/td><td>Strong covalent bonds throughout the sheet<\/td><td>Reinforcing composites and lightweight materials<\/td><\/tr>\n<tr><td><strong>Excellent electrical conductor<\/strong><\/td><td>Delocalised electrons move freely across the sheet<\/td><td>Flexible electronics, touchscreens, sensors<\/td><\/tr>\n<tr><td><strong>Very good thermal conductor<\/strong><\/td><td>Vibrations pass easily through the rigid covalent network<\/td><td>Heat management in electronic devices<\/td><\/tr>\n<tr><td><strong>Transparent and flexible<\/strong><\/td><td>A single atomic layer absorbs little light and can bend without breaking bonds<\/td><td>Transparent conducting films<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-zoom-card\">\n<div class=\"ols-zoom-card-image\">\n<a class=\"ols-lightbox-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/single-graphene-sheet.jpg\" aria-label=\"Open image full screen\">\n<img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/single-graphene-sheet.jpg\" alt=\"A single graphene sheet: a flat honeycomb of carbon hexagons one atom thick\">\n<\/a>\n<\/div>\n<div class=\"ols-zoom-card-caption\"><p>Graphene: one layer of graphite, a two-dimensional giant covalent structure that is strong, flexible and conducting.<\/p><\/div>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Exam sentence:<\/strong> Graphene is a single layer of graphite in which each carbon atom is covalently bonded to three others; the delocalised electrons make it an excellent conductor and the covalent network makes it very strong.<\/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: From Graphene to Nanotubes<\/h2>\n<p>Apply what you know about graphene to two related materials, answering each question as quickly as you can.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-659\" class=\"h5p-iframe\" data-content-id=\"659\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures Quick Fire: From Graphene to Carbon Nanotubes\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card soft\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">5<\/div>\n<h2>Comparing the Three Carbon Structures<\/h2>\n<\/div>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th><\/th><th>Diamond<\/th><th>Graphite<\/th><th>Graphene<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Bonds per carbon atom<\/strong><\/td><td>4<\/td><td>3<\/td><td>3<\/td><\/tr>\n<tr><td><strong>Arrangement<\/strong><\/td><td>Tetrahedral, 109.5\u00b0, three-dimensional<\/td><td>Hexagonal layers, 120\u00b0<\/td><td>One hexagonal layer, 120\u00b0<\/td><\/tr>\n<tr><td><strong>Delocalised electrons<\/strong><\/td><td>None<\/td><td>One per carbon, within each layer<\/td><td>One per carbon, across the sheet<\/td><\/tr>\n<tr><td><strong>Electrical conductivity<\/strong><\/td><td>None<\/td><td>Along the layers<\/td><td>Excellent<\/td><\/tr>\n<tr><td><strong>Hardness<\/strong><\/td><td>Extremely hard<\/td><td>Soft, layers slide<\/td><td>Very strong sheet<\/td><\/tr>\n<tr><td><strong>Melting point<\/strong><\/td><td>Very high<\/td><td>Very high<\/td><td>Very high<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Key idea:<\/strong> The same element gives three very different materials because the bonding arrangement differs: four localised bonds give hardness and no conduction; three bonds plus a delocalised electron give layers that conduct.<\/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: Two Forms of Boron Nitride<\/h2>\n<p>Drag the words into place to compare the two forms of another giant covalent substance.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-437\" class=\"h5p-iframe\" data-content-id=\"437\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Giant Covalent Structures Drag: Two Forms of Boron Nitride\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card soft\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">6<\/div>\n<h2>Where This Sits in the AQA Specification<\/h2>\n<\/div>\n<p>AQA 3.1.3.4 lists macromolecular (giant covalent) crystals alongside ionic, metallic and molecular crystals, and names <strong>diamond and graphite<\/strong> as the examples to know. You should be able to relate their melting points and conductivity to the structure and bonding, and to <strong>draw diagrams of the structures with a specified number of atoms<\/strong>: for diamond, draw a central carbon with its four tetrahedral neighbours and continue outwards; for graphite, draw part of one hexagonal layer and a second layer beneath it. Graphene is not named by AQA but follows directly from graphite.<\/p><div class=\"ols-zoom-card\">\n<div class=\"ols-zoom-card-image\">\n<a class=\"ols-lightbox-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/diamond-and-graphite-bonding-and-structure.jpg\" aria-label=\"Open image full screen\">\n<img decoding=\"async\" class=\"ols-zoomable-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/diamond-and-graphite-bonding-and-structure.jpg\" alt=\"Exam-style sketches of a diamond fragment and a graphite fragment with a specified number of carbon atoms\">\n<\/a>\n<\/div>\n<div class=\"ols-zoom-card-caption\"><p>AQA asks for diagrams with a specified number of particles: a five-atom diamond fragment and a two-layer graphite fragment.<\/p><\/div>\n<\/div>\n<\/article>\n<article class=\"ols-note-card purple\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">7<\/div>\n<h2>Common Exam Mistakes<\/h2>\n<\/div>\n<ul>\n<li>Saying graphite is soft because its covalent bonds are weak. The covalent bonds are strong; it is the forces between layers that are weak.<\/li>\n<li>Saying diamond conducts electricity, or that graphite conducts because it contains ions or is metallic. Only delocalised electrons explain the conduction.<\/li>\n<li>Describing melting as breaking intermolecular forces. In a giant covalent structure the covalent bonds themselves must be broken.<\/li>\n<li>Forgetting the bond angle: 109.5\u00b0 in diamond, 120\u00b0 in graphite and graphene.<\/li>\n<li>Drawing a diamond fragment with carbon atoms that have only three bonds, or a graphite layer with four bonds per carbon.<\/li>\n<\/ul>\n<div class=\"ols-key-box\">\n<p><strong>Exam sentence:<\/strong> Giant covalent structures have very high melting points because many strong covalent bonds must be broken; only those with delocalised electrons, graphite and graphene, conduct electricity.<\/p>\n<\/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, 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top left, rgba(70, 127, 247, 0.14), transparent 34%),\r\n        linear-gradient(135deg, #f8fbff 0%, #e9efff 100%);\r\n      box-shadow: 0 24px 64px rgba(28, 36, 75, 0.18);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-frame-shell iframe {\r\n      display: block;\r\n      width: 100%;\r\n      height: 100%;\r\n      border: 0;\r\n      background: #e9efff;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-overlay {\r\n      position: absolute;\r\n      inset: 0;\r\n      z-index: 5;\r\n      display: flex;\r\n      align-items: center;\r\n      justify-content: center;\r\n      border: 0;\r\n      cursor: pointer;\r\n      background:\r\n        radial-gradient(circle at center, rgba(255, 255, 255, 0.26), rgba(28, 36, 75, 0.28)),\r\n        url(\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/aqa-a-level-chemistry-3-1-3-covalent-bonding-shapes-interactive-course-banner.jpg\");\r\n      background-size: cover;\r\n      background-position: center;\r\n      transition:\r\n        opacity 0.35s ease,\r\n        visibility 0.35s ease;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-overlay::before {\r\n      content: \"\";\r\n      position: absolute;\r\n      inset: 0;\r\n      background: rgba(28, 36, 75, 0.30);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-overlay.is-hidden {\r\n      opacity: 0;\r\n      visibility: hidden;\r\n      pointer-events: none;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-content {\r\n      position: relative;\r\n      z-index: 2;\r\n      display: grid;\r\n      justify-items: center;\r\n      gap: 16px;\r\n      padding: 24px;\r\n      text-align: center;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-play-circle {\r\n      width: 96px;\r\n      height: 96px;\r\n      border-radius: 50%;\r\n      background: #ffffff;\r\n      color: var(--navy);\r\n      display: flex;\r\n      align-items: center;\r\n      justify-content: center;\r\n      box-shadow:\r\n        0 18px 40px rgba(28, 36, 75, 0.30),\r\n        0 0 0 12px rgba(255, 255, 255, 0.22);\r\n      animation: olsAnimationPlayPulse001 1.8s ease-in-out infinite;\r\n      transition:\r\n        transform 0.25s ease,\r\n        background 0.25s ease,\r\n        color 0.25s ease;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-overlay:hover .ols-animation-play-circle {\r\n      transform: scale(1.08);\r\n      background: var(--navy);\r\n      color: #ffffff;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-play-icon {\r\n      width: 0;\r\n      height: 0;\r\n      margin-left: 7px;\r\n      border-top: 18px solid transparent;\r\n      border-bottom: 18px solid transparent;\r\n      border-left: 28px solid currentColor;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-start-text {\r\n      max-width: 540px;\r\n      margin: 0;\r\n      color: #ffffff;\r\n      font-size: clamp(20px, 3vw, 32px);\r\n      line-height: 1.2;\r\n      font-weight: 800;\r\n      text-shadow: 0 8px 20px rgba(0, 0, 0, 0.28);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-pause-button {\r\n      position: absolute;\r\n      left: 16px;\r\n      bottom: 16px;\r\n      z-index: 7;\r\n      display: none;\r\n      align-items: center;\r\n      justify-content: center;\r\n      min-width: 92px;\r\n      padding: 10px 16px;\r\n      border: 0;\r\n      border-radius: 999px;\r\n      background: rgba(28, 36, 75, 0.92);\r\n      color: #ffffff;\r\n      font-family: Poppins, Arial, sans-serif;\r\n      font-size: 14px;\r\n      line-height: 1.2;\r\n      font-weight: 800;\r\n      cursor: pointer;\r\n      box-shadow: 0 12px 28px rgba(28, 36, 75, 0.24);\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-animation-pause-button:hover {\r\n      transform: translateY(-2px);\r\n      background: var(--blue);\r\n      box-shadow: 0 16px 34px rgba(37, 99, 235, 0.28);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-animation-pause-button.is-visible {\r\n      display: inline-flex;\r\n    }\r\n\r\n    @keyframes olsAnimationPlayPulse001 {\r\n      0% {\r\n        box-shadow:\r\n          0 18px 40px rgba(28, 36, 75, 0.30),\r\n          0 0 0 0 rgba(255, 255, 255, 0.40);\r\n      }\r\n\r\n      70% {\r\n        box-shadow:\r\n          0 18px 40px rgba(28, 36, 75, 0.30),\r\n          0 0 0 18px rgba(255, 255, 255, 0);\r\n      }\r\n\r\n      100% {\r\n        box-shadow:\r\n          0 18px 40px rgba(28, 36, 75, 0.30),\r\n          0 0 0 0 rgba(255, 255, 255, 0);\r\n      }\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-video-status {\r\n      margin: 14px 0 0;\r\n      text-align: center;\r\n      color: var(--grey-text);\r\n      font-size: 13px;\r\n      line-height: 1.5;\r\n      font-weight: 500;\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-cta-bottom {\r\n      display: flex;\r\n      justify-content: center;\r\n      padding-top: 22px;\r\n      border-top: 1px solid var(--border);\r\n    }\r\n\r\n    .ols-course-cta-covalent .ols-course-button {\r\n      display: 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-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-3-1-3-aqa\/\" aria-label=\"Open the AQA A Level Chemistry 3.1.3 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\/aqa-a-level-chemistry-3-1-3-covalent-bonding-shapes-interactive-course-banner.jpg\"\r\n            alt=\"AQA A Level Chemistry 3.1.3 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            AQA 7405 | 3.1.3 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-3-1-3-aqa\/\">\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 AQA 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 3.1.3 Covalent Bonding and Shapes of Molecules course. The three guided video lessons are ready now; the AQA MCQ bank, teacher-marked short-answer questions, supplementary lessons 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 3.1.3 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-3-1-3-aqa\/\">\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  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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.saq-question-area{\r\n  height:335px;\r\n  background:#eaf0ff;\r\n  padding:30px 40px 32px;\r\n}\r\n\r\n.saq-question-text{\r\n  font-size:25px;\r\n  line-height:1.42;\r\n  color:#111827;\r\n  margin-bottom:22px;\r\n}\r\n\r\n.saq-student-box{\r\n  height:195px;\r\n  background:#f3f4f6;\r\n  border:2px solid #cfd6e3;\r\n  border-radius:8px;\r\n  padding:23px 26px;\r\n  font-size:24px;\r\n  line-height:1.55;\r\n  color:#4b5563;\r\n  position:relative;\r\n  overflow:hidden;\r\n}\r\n\r\n.saq-teacher-feedback{\r\n  height:630px;\r\n  background:#dff3e6;\r\n  color:#075f3b;\r\n  padding:28px 40px 30px;\r\n  font-size:23px;\r\n  line-height:1.47;\r\n  opacity:0;\r\n  transform:translateY(20px);\r\n  transition:opacity 0.7s ease,transform 0.7s ease;\r\n  overflow:hidden;\r\n}\r\n\r\n.saq-teacher-feedback.show{\r\n  opacity:1;\r\n  transform:translateY(0);\r\n}\r\n\r\n#saqTeacherText{\r\n  white-space:pre-wrap;\r\n}\r\n\r\n.saq-teacher-cursor{\r\n  background:#075f3b;\r\n}\r\n\r\n@media(max-width:900px){\r\n  .ols-video-title,\r\n  .ols-mcq-intro-title,\r\n  .ols-saq-intro-title{\r\n    font-size:clamp(42px,11vw,78px);\r\n    line-height:1.12;\r\n  }\r\n\r\n  .ols-title-cursor{\r\n    width:4px;\r\n    margin-left:6px;\r\n  }\r\n\r\n  .ols-video-card{\r\n    border-radius:20px;\r\n  }\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\" 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Polar Molecules<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/ionic-bonding\/nature-of-ionic-bonding\/\">Nature of Ionic Bonding<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/metallic-bonding\/metallic-bonding-and-structure\/\">Metallic Bonding and Structure<\/a>\n        <\/div>\n      <\/section>\n\n      <section class=\"ols-attribution-card\">\n        <p><strong>Copyright and author footprint:<\/strong> This OLS revision page was written for Online Learning System by <strong>Dr. Mohammed Al-Fatah<\/strong>. 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