{"id":162822,"date":"2025-11-09T03:09:30","date_gmt":"2025-11-09T03:09:30","guid":{"rendered":"https:\/\/news.gyankatta.org\/?p=162822"},"modified":"2025-11-09T03:26:00","modified_gmt":"2025-11-09T03:26:00","slug":"class-11-chemistry-chemical-bonding-and-molecular-structure-only-4-1","status":"publish","type":"post","link":"https:\/\/news.gyankatta.org\/?p=162822","title":{"rendered":"Class 11 Chemistry: CHEMICAL BONDING AND MOLECULAR STRUCTURE (Only 4.1)"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/manishchandra.org\/p7\/dihydro835799640.png\" alt=\"\"\/><\/figure>\n\n\n\n<!-- === Chapter Title Section === -->\n<section class=\"cbms-header\">\n  <div class=\"cbms-header-content\">\n    <h2>4. CHEMICAL BONDING AND MOLECULAR STRUCTURE<\/h2>\n    <ul>\n      <li>4.1 K\u00d6ssel\u2013Lewis Approach to Chemical Bonding<\/li>\n      <li>4.1.1 Octet Rule<\/li>\n      <li>4.1.2 Covalent Bond<\/li>\n      <li>4.1.3 Lewis Representation of Simple Molecules (the Lewis Structures)<\/li>\n      <li>4.1.4 Formal Charge<\/li>\n      <li>4.1.5 Limitations of the Octet Rule<\/li>\n    <\/ul>\n  <\/div>\n<\/section>\n\n<style>\n  .cbms-header {\n    background: linear-gradient(90deg,#1e3a8a,#3b82f6,#06b6d4);\n    color: #f9fafb;\n    border-radius: 18px;\n    padding: 32px 26px;\n    margin: 28px auto 42px;\n    max-width: 900px;\n    box-shadow: 0 12px 40px rgba(37,99,235,0.25);\n  }\n\n  .cbms-header-content h2 {\n    font-family: \"Poppins\", \"Segoe UI\", system-ui, sans-serif;\n    font-size: 1.8rem;\n    margin-bottom: 16px;\n    letter-spacing: 0.3px;\n    background: linear-gradient(to right, #ffffff, #dbeafe);\n    -webkit-background-clip: text;\n    -webkit-text-fill-color: transparent;\n  }\n\n  .cbms-header-content ul {\n    list-style: none;\n    margin: 0;\n    padding: 0;\n    font-family: Inter, system-ui, sans-serif;\n    font-size: 1rem;\n  }\n\n  .cbms-header-content li {\n    margin: 6px 0;\n    padding-left: 20px;\n    position: relative;\n  }\n\n  .cbms-header-content li::before {\n    content: \"\u25b9\";\n    position: absolute;\n    left: 0;\n    color: #a5f3fc;\n  }\n<\/style>\n<style>\n  \/* Container styles *\/\n  .cbms-accordion {\n    --accent: linear-gradient(90deg,#6EE7B7,#3B82F6);\n    max-width: 900px;\n    margin: 28px auto;\n    font-family: Inter, system-ui, -apple-system, \"Segoe UI\", Roboto, \"Helvetica Neue\", Arial;\n    color: #0f172a;\n    line-height: 1.5;\n  }\n\n  \/* Card *\/\n  .cbms-card {\n    background: linear-gradient(180deg, rgba(255,255,255,0.65), rgba(255,255,255,0.5));\n    backdrop-filter: blur(6px) saturate(120%);\n    border-radius: 14px;\n    box-shadow: 0 8px 30px rgba(12, 18, 40, 0.08);\n    border: 1px solid rgba(99,102,241,0.06);\n    margin: 12px 0;\n    overflow: hidden;\n    transition: transform .18s ease, box-shadow .18s ease;\n  }\n  .cbms-card:hover { transform: translateY(-4px); box-shadow: 0 18px 50px rgba(12,18,40,0.12); }\n\n  \/* Question button *\/\n  .cbms-q {\n    display:flex;\n    align-items:center;\n    gap:16px;\n    padding: 18px 20px;\n    cursor: pointer;\n    background: linear-gradient(90deg, rgba(99,102,241,0.04), rgba(99,102,241,0.02));\n    border: none;\n    width:100%;\n    text-align:left;\n    font-weight: 600;\n    font-size: 16px;\n    color: #07203a;\n  }\n\n  .cbms-number {\n    min-width:46px;\n    min-height:46px;\n    display:grid;\n    place-items:center;\n    border-radius:10px;\n    background: var(--accent);\n    color:white;\n    font-weight:700;\n    box-shadow: 0 6px 20px rgba(59,130,246,0.18);\n    font-size:14px;\n  }\n\n  .cbms-title { flex:1; }\n\n  \/* chevron *\/\n  .cbms-chevron {\n    width:36px;height:36px;\n    display:grid;place-items:center;\n    border-radius:10px;\n    transition: transform .22s ease;\n    color: #0f172a;\n    font-size:18px;\n    background: rgba(15,23,42,0.03);\n  }\n\n  \/* Explanation area *\/\n  .cbms-body {\n    padding: 18px 20px 24px 84px;\n    font-size: 14.5px;\n    color: #0b2540;\n    background: linear-gradient(180deg, rgba(250,250,255,0.6), rgba(250,250,255,0.4));\n    border-top: 1px solid rgba(12,18,40,0.03);\n    display:none;\n  }\n\n  .cbms-card[aria-expanded=\"true\"] .cbms-body { display:block; animation: slideIn .22s ease; }\n  .cbms-card[aria-expanded=\"true\"] .cbms-chevron { transform: rotate(180deg); }\n\n  @keyframes slideIn {\n    from { opacity: 0; transform: translateY(-6px); }\n    to { opacity: 1; transform: translateY(0); }\n  }\n\n  \/* mobile spacing *\/\n  @media (max-width:640px){\n    .cbms-body { padding-left: 18px; }\n    .cbms-q{ padding:14px; gap:12px; }\n  }\n<\/style>\n\n<section class=\"cbms-accordion\" aria-label=\"Chemical Bonding Questions\">\n  <!-- Q1 -->\n  <article class=\"cbms-card\" id=\"q1\" role=\"region\" aria-labelledby=\"q1-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q1-btn\" aria-controls=\"q1-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q1')\">\n      <span class=\"cbms-number\">Q1<\/span>\n      <span class=\"cbms-title\">When you put table salt (NaCl) in water and switch on a light bulb connected to it, the bulb glows. This happens because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q1-body\">\n      When NaCl dissolves in water, it splits into Na\u207a and Cl\u207b ions that move freely, conducting electricity. The ions \u2014 not free electrons \u2014 carry charge through the solution. Solid NaCl cannot conduct because its ions are locked in the crystal lattice; only when they dissociate in water do they act as charge carriers.\n    <\/div>\n  <\/article>\n\n  <!-- Q2 -->\n  <article class=\"cbms-card\" id=\"q2\" role=\"region\" aria-labelledby=\"q2-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q2-btn\" aria-controls=\"q2-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q2')\">\n      <span class=\"cbms-number\">Q2<\/span>\n      <span class=\"cbms-title\">When metallic sodium is dropped in water it explodes, but table salt (NaCl) is safe to eat because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q2-body\">\n      Sodium metal is highly reactive because it readily loses electrons to achieve a stable noble-gas configuration; that rapid oxidation in water releases lots of energy and hydrogen gas. In NaCl, sodium exists as Na\u207a and chlorine as Cl\u207b \u2014 both already have electron configurations analogous to noble gases, so the ionic compound is stable and non-reactive under normal conditions.\n    <\/div>\n  <\/article>\n\n  <!-- Q3 -->\n  <article class=\"cbms-card\" id=\"q3\" role=\"region\" aria-labelledby=\"q3-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q3-btn\" aria-controls=\"q3-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q3')\">\n      <span class=\"cbms-number\">Q3<\/span>\n      <span class=\"cbms-title\">Magnesium is used in fireworks, yet forms MgCl\u2082 when reacting with chlorine gas because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q3-body\">\n      Magnesium has two valence electrons in its outer shell and can lose both to form Mg\u00b2\u207a, reaching a noble-gas-like configuration. Each chlorine atom gains one electron to become Cl\u207b, so two chlorine atoms balance one Mg\u00b2\u207a, giving the stable ionic formula MgCl\u2082. This electron transfer is energetically favorable and explains the product formed.\n    <\/div>\n  <\/article>\n\n  <!-- Q4 -->\n  <article class=\"cbms-card\" id=\"q4\" role=\"region\" aria-labelledby=\"q4-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q4-btn\" aria-controls=\"q4-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q4')\">\n      <span class=\"cbms-number\">Q4<\/span>\n      <span class=\"cbms-title\">When you crush salt crystals with a hammer, they shatter rather than bend because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q4-body\">\n      Ionic solids like NaCl are held together by strong electrostatic attraction between oppositely charged ions. Under stress, ionic layers can shift so like charges align; the resulting strong repulsive forces cause the crystal to cleave and shatter. That combination of strong bonding and rigid lattice yields hardness but also brittleness.\n    <\/div>\n  <\/article>\n\n  <!-- Q5 -->\n  <article class=\"cbms-card\" id=\"q5\" role=\"region\" aria-labelledby=\"q5-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q5-btn\" aria-controls=\"q5-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q5')\">\n      <span class=\"cbms-number\">Q5<\/span>\n      <span class=\"cbms-title\">Helium used in balloons doesn\u2019t react with air or catch fire because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q5-body\">\n      Noble gases such as helium have complete valence shells (a full duet for helium, full octets for larger noble gases), providing maximal electronic stability. Because their outer shells are already filled they have little tendency to gain, lose, or share electrons \u2014 making them chemically inert and safe for uses like lifting balloons.\n    <\/div>\n  <\/article>\n\n  <!-- Q6 -->\n  <article class=\"cbms-card\" id=\"q6\" role=\"region\" aria-labelledby=\"q6-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q6-btn\" aria-controls=\"q6-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q6')\">\n      <span class=\"cbms-number\">Q6<\/span>\n      <span class=\"cbms-title\">Cooking gas (LPG) doesn\u2019t react with air until ignited because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q6-body\">\n      Propane and butane molecules are held by strong covalent bonds; each atom satisfies its octet (or duet for hydrogen), so there are no unpaired electrons or free ions to react spontaneously at room temperature. Energy input (a spark or flame) is needed to break bonds and start combustion.\n    <\/div>\n  <\/article>\n\n  <!-- Q7 -->\n  <article class=\"cbms-card\" id=\"q7\" role=\"region\" aria-labelledby=\"q7-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q7-btn\" aria-controls=\"q7-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q7')\">\n      <span class=\"cbms-number\">Q7<\/span>\n      <span class=\"cbms-title\">Toothpaste contains fluoride ions, yet pure fluorine gas is dangerously reactive because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q7-body\">\n      Fluorine atoms are very small and highly electronegative, strongly attracting electrons to complete their octet; as a result elemental F\u2082 is extremely reactive and forms bonds readily (often violently). In toothpaste we use stable fluoride ions (F\u207b), not elemental fluorine, which are safe and beneficial in small amounts.\n    <\/div>\n  <\/article>\n\n  <!-- Q8 -->\n  <article class=\"cbms-card\" id=\"q8\" role=\"region\" aria-labelledby=\"q8-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q8-btn\" aria-controls=\"q8-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q8')\">\n      <span class=\"cbms-number\">Q8<\/span>\n      <span class=\"cbms-title\">An old iron gate rusts over time mainly because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q8-body\">\n      Rusting is an oxidation process: iron atoms lose electrons (are oxidized) to oxygen in the presence of moisture, forming iron oxides and hydroxides. By losing electrons, the iron atoms move toward a more stable electronic arrangement \u2014 the whole electrochemical process explains the familiar corrosion of metal structures.\n    <\/div>\n  <\/article>\n\n  <!-- Q9 -->\n  <article class=\"cbms-card\" id=\"q9\" role=\"region\" aria-labelledby=\"q9-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q9-btn\" aria-controls=\"q9-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q9')\">\n      <span class=\"cbms-number\">Q9<\/span>\n      <span class=\"cbms-title\">When you dip a tester in pure water, it doesn\u2019t glow, but it does in saltwater because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q9-body\">\n      Pure water contains very few ions and therefore cannot carry current well. Adding salt (NaCl) produces Na\u207a and Cl\u207b ions in solution that are free to move under an electric field \u2014 these mobile ions are the charge carriers that make the tester glow.\n    <\/div>\n  <\/article>\n\n  <!-- Q10 -->\n  <article class=\"cbms-card\" id=\"q10\" role=\"region\" aria-labelledby=\"q10-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q10-btn\" aria-controls=\"q10-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q10')\">\n      <span class=\"cbms-number\">Q10<\/span>\n      <span class=\"cbms-title\">Plastic chairs are strong yet lightweight because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q10-body\">\n      Plastics are polymers: long chains of repeating units bonded by strong covalent bonds. These covalent networks resist breakage and distribute stress across the chain, giving materials high strength-to-weight ratios. Chemical resistance also arises from the stability of the covalent backbone.\n    <\/div>\n  <\/article>\n\n  <!-- Q11 -->\n  <article class=\"cbms-card\" id=\"q11\" role=\"region\" aria-labelledby=\"q11-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q11-btn\" aria-controls=\"q11-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q11')\">\n      <span class=\"cbms-number\">Q11<\/span>\n      <span class=\"cbms-title\">The oxygen you breathe remains stable in air because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q11-body\">\n      Molecular oxygen (O\u2082) contains a double covalent bond where each oxygen shares two pairs of electrons, completing their octets. This shared electron arrangement is energetically favorable and explains why O\u2082 is a stable, diatomic gas under normal conditions.\n    <\/div>\n  <\/article>\n\n  <!-- Q12 -->\n  <article class=\"cbms-card\" id=\"q12\" role=\"region\" aria-labelledby=\"q12-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q12-btn\" aria-controls=\"q12-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q12')\">\n      <span class=\"cbms-number\">Q12<\/span>\n      <span class=\"cbms-title\">Carbon forms thousands of substances like fuels, plastics, and biomolecules because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q12-body\">\n      Carbon is tetravalent \u2014 it can form four covalent bonds \u2014 and it readily bonds to other carbon atoms (catenation), creating long chains, branched frameworks, and rings. This versatility is the fundamental reason for the vast diversity of organic compounds found in fuels, polymers, and living systems.\n    <\/div>\n  <\/article>\n\n  <!-- Q13 -->\n  <article class=\"cbms-card\" id=\"q13\" role=\"region\" aria-labelledby=\"q13-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q13-btn\" aria-controls=\"q13-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q13')\">\n      <span class=\"cbms-number\">Q13<\/span>\n      <span class=\"cbms-title\">The carbon dioxide you exhale stays unreactive in the air because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q13-body\">\n      Carbon dioxide (CO\u2082) is linear with carbon forming two double bonds to oxygen. Each atom attains an octet through these shared pairs, producing a stable, symmetric, and relatively non-reactive molecule under ordinary atmospheric conditions.\n    <\/div>\n  <\/article>\n\n  <!-- Q14 -->\n  <article class=\"cbms-card\" id=\"q14\" role=\"region\" aria-labelledby=\"q14-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q14-btn\" aria-controls=\"q14-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q14')\">\n      <span class=\"cbms-number\">Q14<\/span>\n      <span class=\"cbms-title\">Ammonia (used in cleaners) dissolves easily in water, but methane (natural gas) doesn\u2019t because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q14-body\">\n      Ammonia (NH\u2083) has a lone pair on nitrogen and a trigonal pyramidal shape, creating a permanent dipole that interacts favorably with polar water molecules. Methane (CH\u2084) is tetrahedral and symmetric, producing no net dipole; its non-polar nature prevents it from dissolving appreciably in water.\n    <\/div>\n  <\/article>\n\n  <!-- Q15 -->\n  <article class=\"cbms-card\" id=\"q15\" role=\"region\" aria-labelledby=\"q15-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q15-btn\" aria-controls=\"q15-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q15')\">\n      <span class=\"cbms-number\">Q15<\/span>\n      <span class=\"cbms-title\">Ozone in the upper atmosphere protects us from UV rays because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q15-body\">\n      Ozone (O\u2083) has resonance structures with electrons delocalized across the molecule. These electronic arrangements allow ozone to absorb ultraviolet radiation, converting the energy into chemical forms and thereby protecting life on Earth while still being reactive enough to reform the ozone layer.\n    <\/div>\n  <\/article>\n\n  <!-- Q16 -->\n  <article class=\"cbms-card\" id=\"q16\" role=\"region\" aria-labelledby=\"q16-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q16-btn\" aria-controls=\"q16-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q16')\">\n      <span class=\"cbms-number\">Q16<\/span>\n      <span class=\"cbms-title\">Dry ice used for fog effects doesn\u2019t conduct electricity because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q16-body\">\n      Solid CO\u2082 (dry ice) is composed of neutral covalent CO\u2082 molecules held together by weak van der Waals forces. There are no mobile ions or delocalized electrons in the solid state, so it cannot conduct electricity like ionic solids or metals.\n    <\/div>\n  <\/article>\n\n  <!-- Q17 -->\n  <article class=\"cbms-card\" id=\"q17\" role=\"region\" aria-labelledby=\"q17-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q17-btn\" aria-controls=\"q17-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q17')\">\n      <span class=\"cbms-number\">Q17<\/span>\n      <span class=\"cbms-title\">In fertilizers containing nitrate ions (NO\u2083\u207b), the negative charge behaves as if spread across all oxygens because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q17-body\">\n      Nitrate is a resonance-stabilized ion: the negative charge is delocalized over three equivalent oxygen atoms. Formal charge calculations and resonance structures together show that the negative charge is shared, which explains uniform reactivity and bond lengths observed experimentally.\n    <\/div>\n  <\/article>\n\n  <!-- Q18 -->\n  <article class=\"cbms-card\" id=\"q18\" role=\"region\" aria-labelledby=\"q18-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q18-btn\" aria-controls=\"q18-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q18')\">\n      <span class=\"cbms-number\">Q18<\/span>\n      <span class=\"cbms-title\">Chemists draw several Lewis structures for a molecule and choose the most stable one using formal charge because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q18-body\">\n      Formal charge analysis helps minimize charge separation and select the Lewis structure that best reflects electron distribution. The structure with the smallest and most appropriate formal charges usually corresponds to lower energy and higher stability \u2014 a practical tool in predicting molecular arrangements.\n    <\/div>\n  <\/article>\n\n  <!-- Q19 -->\n  <article class=\"cbms-card\" id=\"q19\" role=\"region\" aria-labelledby=\"q19-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q19-btn\" aria-controls=\"q19-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q19')\">\n      <span class=\"cbms-number\">Q19<\/span>\n      <span class=\"cbms-title\">Chalk (CaCO\u2083) doesn\u2019t decompose easily because the CO\u2083\u00b2\u207b ion inside it is stable due to:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q19-body\">\n      The carbonate ion features resonance that delocalizes the two negative charges across three equivalent oxygen atoms. This delocalization lowers the ion\u2019s energy and contributes to the stability of carbonate salts like chalk, making them relatively resistant to decomposition under mild conditions.\n    <\/div>\n  <\/article>\n\n  <!-- Q20 -->\n  <article class=\"cbms-card\" id=\"q20\" role=\"region\" aria-labelledby=\"q20-btn\" aria-expanded=\"false\">\n    <button class=\"cbms-q\" id=\"q20-btn\" aria-controls=\"q20-body\" aria-expanded=\"false\" onclick=\"toggleCard(event,'q20')\">\n      <span class=\"cbms-number\">Q20<\/span>\n      <span class=\"cbms-title\">Compounds like PCl\u2085 used in chemical labs exist even though phosphorus has 10 electrons in its valence shell because:<\/span>\n      <span class=\"cbms-chevron\">\u2304<\/span>\n    <\/button>\n    <div class=\"cbms-body\" id=\"q20-body\">\n      Elements in the third period, such as phosphorus, have access to vacant d-orbitals which allow them to expand their valence shell beyond eight electrons. This capacity to accommodate more electrons explains stable molecules with expanded octets like PCl\u2085 and SF\u2086.\n    <\/div>\n  <\/article>\n<\/section>\n\n<script>\n  \/\/ Toggle logic: allow one open card at a time. 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CHEMICAL BONDING AND MOLECULAR STRUCTURE 4.1 K\u00d6ssel\u2013Lewis Approach to Chemical Bonding 4.1.1 Octet Rule 4.1.2 Covalent Bond 4.1.3 Lewis Representation of Simple Molecules (the Lewis Structures) 4.1.4 Formal Charge 4.1.5 Limitations of the Octet Rule Q1 When you put table salt (NaCl) in water and switch on a light bulb connected to it, the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-162822","post","type-post","status-publish","format-standard","hentry","category-uncategorized","cat-1-id"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Class 11 Chemistry: CHEMICAL BONDING AND MOLECULAR STRUCTURE (Only 4.1) - Gyankatta %<\/title>\n<meta name=\"description\" content=\"Explore 20 real-life Class 11 Chemistry MCQs from Chapter 4: Chemical Bonding and Molecular Structure. 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