{"id":10472,"date":"2026-09-26T11:30:20","date_gmt":"2026-09-26T10:30:20","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/"},"modified":"2026-10-04T23:02:31","modified_gmt":"2026-10-04T22:02:31","slug":"8c-group-7","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/","title":{"rendered":"Topic 8C Group 7"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-topic-8c-landing-page\">\n  <style>\n    .ols-revision-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --soft-blue: #eef4ff;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-green: #f0f7f1;\n      --soft-orange: #fff7ed;\n      --gold: #c9973a;\n      --grey-text: #667085;\n      --body-text: #1f2937;\n      --border: rgba(28, 36, 75, 0.14);\n      --shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      --inner-shadow: 0 10px 26px rgba(28, 36, 75, 0.08);\n      font-family: Poppins, Arial, sans-serif;\n      color: var(--navy);\n      background: #ffffff;\n    }\n\n    .ols-revision-page * { box-sizing: border-box; }\n\n    .ols-revision-layout {\n      display: block;\n      max-width: 1450px;\n      margin: 0 auto;\n      padding: 24px 20px 60px;\n    }\n\n    .ols-breadcrumbs {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 8px;\n      margin: 10px 0 22px;\n      font-size: 15px;\n      color: var(--grey-text);\n    }\n\n    .ols-breadcrumbs a,\n    .ols-breadcrumbs span {\n      color: var(--grey-text);\n      text-decoration: none;\n      font-weight: 600;\n    }\n\n    .ols-breadcrumbs a:hover {\n      color: var(--blue);\n      text-decoration: underline;\n      text-underline-offset: 3px;\n    }\n\n    .ols-title-card,\n    .ols-note-card,\n    .ols-related-card,\n    .ols-attribution-card {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 28px;\n      box-shadow: var(--shadow);\n      padding: 34px;\n      margin-bottom: 24px;\n      overflow: hidden;\n    }\n\n    .ols-title-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-title-card h1 {\n      margin: 0 0 18px;\n      font-size: clamp(36px, 5vw, 58px);\n      line-height: 1.08;\n      font-weight: 800;\n      letter-spacing: -0.04em;\n      color: #111827;\n    }\n\n    .ols-page-intro {\n      font-size: 19px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--body-text);\n      margin: 0 0 22px;\n    }\n\n    .ols-badges {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 12px;\n      margin-bottom: 22px;\n    }\n\n    .ols-badge {\n      display: inline-flex;\n      align-items: center;\n      padding: 9px 14px;\n      border-radius: 999px;\n      background: #ffffff;\n      border: 1px solid var(--border);\n      font-size: 15px;\n      font-weight: 600;\n      color: var(--navy);\n    }\n\n    .ols-author {\n      display: flex;\n      align-items: center;\n      gap: 20px;\n      padding: 28px;\n      border-radius: 28px;\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      border: 1px solid rgba(28,36,75,0.12);\n      box-shadow: 0 18px 45px rgba(28,36,75,0.10);\n      margin-top: 22px;\n    }\n\n    .ols-author-avatar-img {\n      width: 92px;\n      height: 92px;\n      border-radius: 50%;\n      object-fit: cover;\n      object-position: center;\n      flex-shrink: 0;\n      border: 4px solid #ffffff;\n      box-shadow: 0 14px 32px rgba(28,36,75,0.18), 0 0 0 1px rgba(28,36,75,0.10);\n      transition: transform 0.25s ease, box-shadow 0.25s ease;\n    }\n\n    .ols-author:hover .ols-author-avatar-img {\n      transform: scale(1.04);\n      box-shadow: 0 20px 42px rgba(28,36,75,0.22), 0 0 0 1px rgba(28,36,75,0.10);\n    }\n\n    .ols-author-content { min-width: 0; }\n\n    .ols-author-title {\n      margin: 0 0 4px;\n      font-size: clamp(24px,3vw,34px);\n      line-height: 1.15;\n      font-weight: 700;\n      color: var(--navy);\n      letter-spacing: -0.03em;\n    }\n\n    .ols-author-description {\n      margin: 0;\n      font-size: 17px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--grey-text);\n    }\n\n    .ols-linkedin-pill {\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      gap: 10px;\n      margin-top: 16px;\n      padding: 11px 18px;\n      border-radius: 999px;\n      background: linear-gradient(135deg,#0A66C2,#004182);\n      color: #ffffff;\n      text-decoration: none;\n      font-size: 14px;\n      line-height: 1;\n      font-weight: 700;\n      letter-spacing: 0.01em;\n      box-shadow: 0 10px 22px rgba(10,102,194,0.24);\n      position: relative;\n      overflow: hidden;\n      transition: transform 0.22s ease, box-shadow 0.22s ease;\n    }\n\n    .ols-linkedin-pill::before {\n      content: \"\";\n      position: absolute;\n      top: 0;\n      left: -120%;\n      width: 100%;\n      height: 100%;\n      background: linear-gradient(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0) 100%);\n      transition: left 0.7s ease;\n    }\n\n    .ols-linkedin-pill:hover {\n      transform: translateY(-3px) scale(1.03);\n      box-shadow: 0 16px 34px rgba(10,102,194,0.34), 0 0 0 6px rgba(10,102,194,0.10);\n      color: #ffffff;\n    }\n\n    .ols-linkedin-pill:hover::before { left: 120%; }\n\n    .ols-linkedin-icon {\n      width: 18px;\n      height: 18px;\n      display: block;\n      flex-shrink: 0;\n    }\n\n    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%); }\n\n    .ols-note-title {\n      display: flex;\n      align-items: center;\n      gap: 14px;\n      margin-bottom: 20px;\n    }\n\n    .ols-note-icon {\n      width: 52px;\n      height: 52px;\n      border-radius: 16px;\n      background: var(--navy);\n      color: #ffffff;\n      display: grid;\n      place-items: center;\n      font-size: 24px;\n      font-weight: 800;\n      flex-shrink: 0;\n    }\n\n    .ols-note-title h2,\n    .ols-related-card h2 {\n      margin: 0;\n      font-size: clamp(28px, 3.5vw, 42px);\n      line-height: 1.15;\n      font-weight: 800;\n      color: #111827;\n      letter-spacing: -0.03em;\n    }\n\n    .ols-related-card h2 { margin-bottom: 14px; }\n\n    .ols-note-card p,\n    .ols-note-card li,\n    .ols-related-card p,\n    .ols-attribution-card p {\n      font-size: clamp(15px, 1.3vw, 18px);\n      line-height: 1.65;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-note-card strong,\n    .ols-related-card strong,\n    .ols-attribution-card strong {\n      font-weight: 700;\n      color: var(--navy);\n    }\n\n    .ols-key-box {\n      margin-top: 20px;\n      background: var(--soft-green);\n      border: 1px solid rgba(63, 143, 70, 0.25);\n      border-radius: 20px;\n      padding: 18px 20px;\n    }\n\n    .ols-key-box p {\n      margin: 0;\n      font-weight: 400;\n      color: var(--navy);\n    }\n\n    .ols-ert-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 18px;\n      margin-top: 26px;\n    }\n\n    .ols-ert-card {\n      position: relative;\n      display: grid;\n      grid-template-rows: auto 1fr auto;\n      min-height: 285px;\n      padding: 24px;\n      border-radius: 24px;\n      border: 1px solid rgba(28, 36, 75, 0.13);\n      background:\n        radial-gradient(circle at top right, rgba(37, 99, 235, 0.13), transparent 34%),\n        linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      color: var(--navy);\n      text-decoration: none;\n      overflow: hidden;\n      box-shadow: var(--inner-shadow);\n      transition: transform 0.24s ease, box-shadow 0.24s ease, border-color 0.24s ease, background 0.24s ease;\n    }\n\n    .ols-ert-card:hover {\n      transform: translateY(-6px);\n      border-color: rgba(37, 99, 235, 0.28);\n      box-shadow: 0 24px 52px rgba(28, 36, 75, 0.15);\n      color: var(--navy);\n    }\n\n    .ols-ert-card::before {\n      content: \"\";\n      position: absolute;\n      top: -60px;\n      right: -60px;\n      width: 145px;\n      height: 145px;\n      border-radius: 50%;\n      background: rgba(37, 99, 235, 0.08);\n      transition: transform 0.28s ease, background 0.28s ease;\n    }\n\n    .ols-ert-card:hover::before {\n      transform: scale(1.22);\n      background: rgba(37, 99, 235, 0.13);\n    }\n\n    .ols-ert-visual {\n      position: relative;\n      z-index: 1;\n      min-height: 94px;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      margin-bottom: 18px;\n    }\n\n    .ols-ert-icon {\n      position: relative;\n      width: 150px;\n      height: 94px;\n    }\n\n    .ols-ert-line,\n    .ols-ert-arrow,\n    .ols-ert-label-mini,\n    .ols-ert-ion,\n    .ols-ert-pull,\n    .ols-ert-lattice {\n      position: absolute;\n      display: block;\n    }\n\n    .ols-ert-ionic .ols-ert-ion {\n      width: 40px;\n      height: 40px;\n      border-radius: 50%;\n      display: grid;\n      place-items: center;\n      font-size: 15px;\n      font-weight: 800;\n      color: #ffffff;\n      box-shadow: 0 12px 24px rgba(28,36,75,0.14);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.left {\n      left: 24px;\n      top: 24px;\n      background: var(--blue);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.right {\n      right: 24px;\n      top: 24px;\n      background: var(--gold);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow {\n      left: 68px;\n      top: 43px;\n      width: 36px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(28, 36, 75, 0.65);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow::after {\n      content: \"\";\n      position: absolute;\n      right: -1px;\n      top: 50%;\n      transform: translateY(-50%);\n      border-left: 10px solid rgba(28,36,75,0.65);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-ionic .ols-ert-label-mini {\n      left: 39px;\n      bottom: 8px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.large {\n      left: 21px;\n      top: 18px;\n      width: 58px;\n      height: 58px;\n      border-radius: 50%;\n      border: 3px solid rgba(37, 99, 235, 0.34);\n      background: rgba(238, 244, 255, 0.96);\n      box-shadow: inset -10px 0 0 rgba(37,99,235,0.10), 0 12px 24px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.small {\n      right: 33px;\n      top: 30px;\n      width: 34px;\n      height: 34px;\n      border-radius: 50%;\n      background: var(--gold);\n      box-shadow: 0 10px 22px rgba(201,151,58,0.20);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull {\n      left: 82px;\n      top: 44px;\n      width: 34px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before,\n    .ols-ert-polarisation .ols-ert-pull::after {\n      content: \"\";\n      position: absolute;\n      top: 50%;\n      transform: translateY(-50%);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before {\n      left: -1px;\n      border-right: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::after {\n      right: -1px;\n      border-left: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-label-mini {\n      left: 34px;\n      bottom: 8px;\n      color: var(--gold);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-properties .ols-ert-lattice {\n      left: 31px;\n      top: 13px;\n      width: 88px;\n      height: 68px;\n      background:\n        radial-gradient(circle at 12px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 12px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 36px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 60px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 60px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 60px, var(--blue) 0 7px, transparent 8px);\n      border-radius: 18px;\n      box-shadow: 0 12px 26px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-properties .ols-ert-lattice::before {\n      content: \"\";\n      position: absolute;\n      inset: 8px 6px;\n      background:\n        linear-gradient(90deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px,\n        linear-gradient(0deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px;\n      border-radius: 14px;\n      pointer-events: none;\n    }\n\n    .ols-ert-properties .ols-ert-label-mini {\n      left: 43px;\n      bottom: 7px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-card h3 {\n      position: relative;\n      z-index: 1;\n      margin: 0 0 10px;\n      font-size: 23px;\n      line-height: 1.2;\n      font-weight: 800;\n      letter-spacing: -0.02em;\n      color: #111827;\n    }\n\n    .ols-ert-card p {\n      position: relative;\n      z-index: 1;\n      margin: 0;\n      font-size: 15px;\n      line-height: 1.6;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-ert-card,\n    .ols-ert-card *,\n    .ols-ert-card:hover,\n    .ols-ert-card:hover *,\n    .ols-related-item,\n    .ols-related-item *,\n    .ols-related-item:hover,\n    .ols-related-item:hover * {\n      text-decoration: none !important;\n    }\n\n    .ols-ert-meta {\n      position: relative;\n      z-index: 1;\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      margin-top: 20px;\n      padding: 10px 14px;\n      border-radius: 999px;\n      background: var(--navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 700;\n      width: fit-content;\n      transition: background 0.22s ease, transform 0.22s ease;\n    }\n\n    .ols-ert-card:hover .ols-ert-meta {\n      background: var(--blue);\n      transform: translateX(4px);\n    }\n\n    .ols-related-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 16px;\n      margin-top: 18px;\n    }\n\n    .ols-related-item {\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px;\n      background: #ffffff;\n      color: var(--navy);\n      text-decoration: none;\n      font-weight: 600;\n      line-height: 1.5;\n      transition: transform 0.2s ease, box-shadow 0.2s ease, color 0.2s ease;\n    }\n\n    .ols-related-item:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08);\n      color: var(--blue);\n    }\n\n    .ols-attribution-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-attribution-card p {\n      margin: 0;\n      font-size: 14px;\n      color: var(--grey-text);\n    }\n\n    @media (max-width: 1050px) {\n      .ols-revision-layout { grid-template-columns: 1fr; }\n      .ols-main { max-width: none; }\n      .ols-ert-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n      .ols-related-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n    }\n\n    @media (max-width: 760px) {\n      .ols-revision-layout { padding: 14px 12px 44px; }\n      .ols-title-card, .ols-note-card, .ols-related-card, .ols-attribution-card { padding: 24px 18px; border-radius: 22px; }\n      .ols-note-title { align-items: flex-start; }\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      .ols-ert-grid { grid-template-columns: 1fr; }\n      .ols-ert-card { min-height: 255px; }\n      .ols-related-grid { grid-template-columns: 1fr; }\n    }\n  :root { --ols-navy: #1C244B; --ols-blue: #467FF7; --ols-soft-blue: #EEF4FF; --ols-border: rgba(28, 36, 75, 0.12); --ols-shadow: 0 18px 45px rgba(28, 36, 75, 0.12); --ols-shadow-soft: 0 10px 28px rgba(28, 36, 75, 0.09); --ols-muted: #4b5575; }\n    .ols-sub-cards-grid { margin-top: 26px; }\n    .ols-sub-cards-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 20px;\n    }\n\n    .ols-sub-card {\n      display: flex;\n      flex-direction: column;\n      background: #ffffff;\n      border: 1px solid var(--ols-border);\n      border-radius: 22px;\n      overflow: hidden;\n      box-shadow: var(--ols-shadow-soft);\n      text-decoration: none;\n      color: var(--ols-navy);\n      transition:\n        transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),\n        box-shadow 0.28s ease,\n        border-color 0.28s ease;\n      position: relative;\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover {\n      transform: translateY(-10px) scale(1.02);\n      box-shadow: 0 28px 56px rgba(28, 36, 75, 0.16);\n      border-color: rgba(70, 127, 247, 0.35);\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover .ols-sub-card-img-wrap::after {\n      opacity: 1;\n    }\n\n    .ols-sub-card-img-wrap {\n      position: relative;\n      width: 100%;\n      aspect-ratio: 4 \/ 3;\n      background: var(--ols-soft-blue);\n      overflow: hidden;\n    }\n\n    .ols-sub-card-img-wrap::after {\n      content: \"\";\n      position: absolute;\n      inset: 0;\n      background: linear-gradient(180deg, transparent 40%, rgba(28, 36, 75, 0.20) 100%);\n      opacity: 0;\n      transition: opacity 0.28s ease;\n      z-index: 1;\n    }\n\n    .ols-sub-card-num {\n      position: absolute;\n      top: 12px;\n      left: 12px;\n      width: 32px;\n      height: 32px;\n      border-radius: 50%;\n      background: var(--ols-navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 800;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      z-index: 3;\n      box-shadow: 0 4px 12px rgba(28, 36, 75, 0.28);\n    }\n\n    .ols-sub-card-status {\n      position: absolute;\n      top: 12px;\n      right: 12px;\n      padding: 4px 10px;\n      border-radius: 999px;\n      font-size: 10px;\n      font-weight: 700;\n      z-index: 3;\n    }\n\n    .ols-sub-card-status--available {\n      background: #eaf3de;\n      color: #3B6D11;\n    }\n\n    .ols-sub-card-body {\n      padding: 18px 18px 22px;\n      flex: 1;\n      display: flex;\n      flex-direction: column;\n      gap: 6px;\n    }\n\n    .ols-sub-card-title {\n      font-size: 14px;\n      font-weight: 700;\n      color: var(--ols-navy);\n      line-height: 1.35;\n      margin: 0;\n    }\n\n    .ols-sub-card-desc {\n      font-size: 12px;\n      font-weight: 300;\n      color: var(--ols-muted);\n      line-height: 1.6;\n      margin: 0;\n    }\n\n    .ols-sub-card-cta {\n      display: inline-flex;\n      align-items: center;\n      gap: 5px;\n      margin-top: 10px;\n      font-size: 12px;\n      font-weight: 700;\n      color: var(--ols-blue);\n    }\n\n    .ols-sub-card-cta svg {\n      width: 14px;\n      height: 14px;\n      transition: transform 0.2s ease;\n    }\n\n    .ols-sub-card--available:hover .ols-sub-card-cta svg {\n      transform: 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var(--ols-navy);\n    }\n\n    \/* =========================================================\n       SPECIFICATION SECTION\n    ========================================================= *\/\n    @media (max-width: 1024px) { .ols-sub-cards-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }\n    @media (max-width: 640px) { .ols-sub-cards-grid { grid-template-columns: 1fr; gap: 14px; } }\n    .ols-sub-card, .ols-sub-card *, .ols-sub-card:hover, .ols-sub-card:hover * { text-decoration: none !important; }\n    .ols-sub-card--soon { filter: grayscale(1); opacity: 0.62; cursor: not-allowed; }\n    .ols-sub-card-status--soon { background: #6b7280; color: #ffffff; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main { font-size: clamp(19px, 1.9vw, 26px) !important; line-height: 1.08; }\n    .ols-sub-cards-grid .ols-sub-visual-panel { width: min(86%, 270px); padding: 14px; }\n    .ols-sub-card .ols-sub-card-title.ols-sub-card-title { font-size: 14px; font-weight: 700; color: #1C244B; line-height: 1.35; margin: 0; }\n    .ols-sub-card .ols-sub-card-desc.ols-sub-card-desc { font-size: 12px; font-weight: 300; color: #4b5575; line-height: 1.6; margin: 0; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--long { font-size: clamp(15px, 1.35vw, 19px) !important; line-height: 1.12; letter-spacing: -0.03em; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--mid { font-size: clamp(17px, 1.6vw, 22px) !important; }\n    .ols-sub-cards-grid .ols-sub-visual-sub { font-size: 11px; line-height: 1.35; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>A Level Chemistry<\/p>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Topic 8 Redox &amp; Groups 1, 2 and 7<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Overview<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/\">Topic 8A Redox Chemistry<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/oxidation-numbers\/\">Oxidation Numbers<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/electron-transfer-and-half-equations\/\">Electron Transfer and Half-Equations<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/disproportionation\/\">Disproportionation<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/redox-classification\/\">Redox Classification<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/\">Topic 8B Groups 1 and 2<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/trends-down-groups-1-and-2\/\">Trends Down Groups 1 and 2<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/reactions-of-the-group-1-and-2-elements\/\">Reactions of the Group 1 and 2 Elements<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/oxides-hydroxides-and-carbonates\/\">Oxides, Hydroxides and Carbonates<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/solubility-trends-and-the-sulfate-test\/\">Solubility Trends and the Sulfate Test<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/thermal-stability-and-flame-colours\/\">Thermal Stability and Flame Colours<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/tests-for-ions\/\">Tests for Ions<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/titrations-and-measurement-uncertainty\/\">Titrations and Measurement Uncertainty<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-3-concentration-of-hcl-by-titration\/\">Core Practical 3<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-4-preparation-of-a-standard-solution\/\">Core Practical 4<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/\">Topic 8C Group 7<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/trends-in-the-halogens\/\">Trends in the Halogens<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halogens-as-oxidising-agents\/\">Halogens as Oxidising Agents<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/disproportionation-reactions-of-chlorine\/\">Disproportionation Reactions of Chlorine<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halide-ions-reducing-agents-and-tests\/\">Halide Ions: Reducing Agents and Tests<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Other Topics<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-6-energetics\/\">Topic 6 Energetics<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-7-intermolecular-forces\/\">Topic 7 Intermolecular Forces<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-2-atomic-structure-and-the-periodic-table\/\">Topic 2 Atomic Structure &amp; The Periodic Table<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/\">Core Practicals<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\n\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    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'active-main');\r\n          matched.setAttribute('aria-current', 'page');\r\n          matched.setAttribute('tabindex', '-1');\r\n          matched.setAttribute('data-ols-disabled-parent', '1');\r\n        }\r\n      }\r\n    }\r\n\r\n    return true;\r\n  }\r\n\r\n  if (!highlightActive()) {\r\n    document.addEventListener('DOMContentLoaded', highlightActive);\r\n  }\r\n})();\r\n<\/script>\r\n\n\n  <main class=\"ols-main\">\n    <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/\">Edexcel International<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Redox Chemistry and Groups 1, 2 and 7<\/a> \/\n      <span>Topic 8C Group 7<\/span>\n    <\/nav>\n\n    <header class=\"ols-title-card\">\n      <h1>Topic 8C Group 7<\/h1>\n      <p class=\"ols-page-intro\">Use this landing page to move between the four Group 7 revision pages of Topic 8. Each card links to a focused page with inline checks, worked examples and exam-style FAQs.<\/p>\n\n      <div class=\"ols-badges\">\n        <div class=\"ols-badge\">Exam board: Edexcel International<\/div>\n        <div class=\"ols-badge\">Unit 2: WCH12\/01<\/div>\n        <div class=\"ols-badge\">Topic 8C Group 7<\/div>\n      <\/div>\n\n      <div class=\"ols-author\">\n        <img decoding=\"async\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\" alt=\"Dr. Mohammed Al-Fatah\">\n\n        <div class=\"ols-author-content\">\n          <h2 class=\"ols-author-title\">Written by:<br><span>Dr. Mohammed Al-Fatah<\/span><\/h2>\n          <p class=\"ols-author-description\">Chemistry specialist revision notes for A Level Chemistry.<\/p>\n\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\"><\/path>\n            <\/svg>\n            View LinkedIn Profile\n          <\/a>\n        <\/div>\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>Choose a Group 7 Page<\/h2>\n      <\/div>\n\n      <p>Group 7 is the p-block mirror of Group 2: the same reasoning about size and shielding, but now the halogens gain electrons instead of losing them. These pages cover the physical trends, the halogens as oxidising agents, the disproportionation reactions of chlorine and the halide ions as reducing agents together with their tests.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Key idea:<\/strong> Oxidising power falls down the group because the incoming electron is further from the nucleus and more shielded; reducing power of the halide ions rises for exactly the same reason.<\/p>\n      <\/div>\n\n      <div class=\"ols-sub-cards-grid\">\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/trends-in-the-halogens\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">F\u2082 to I\u2082<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Halogen Trends<\/div>\n                <div class=\"ols-sub-visual-sub\">colour, volatility, electronegativity<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">1<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Trends in the Halogens<\/p>\n            <p class=\"ols-sub-card-desc\">The trends in Group 7: states, colours, boiling points, electronegativity, reactivity and predictions for fluorine and astatine.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halogens-as-oxidising-agents\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Displacement<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Oxidising Agents<\/div>\n                <div class=\"ols-sub-visual-sub\">Cl\u2082 > Br\u2082 > I\u2082<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">2<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Halogens as Oxidising Agents<\/p>\n            <p class=\"ols-sub-card-desc\">The halogens as oxidising agents: displacement reactions, colours in water and cyclohexane, reactions with metals and hydrogen, and the reactivity trend.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/disproportionation-reactions-of-chlorine\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Water and bleach<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Chlorine Reactions<\/div>\n                <div class=\"ols-sub-visual-sub\">Cl\u2082 + H\u2082O, Cl\u2082 + NaOH<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">3<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Disproportionation Reactions of Chlorine<\/p>\n            <p class=\"ols-sub-card-desc\">The disproportionation of chlorine with water and with cold and hot alkali, bleach, water treatment and analogous halogen reactions.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halide-ions-reducing-agents-and-tests\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Cl\u207b, Br\u207b, I\u207b<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Halide Ions<\/div>\n                <div class=\"ols-sub-visual-sub\">H\u2082SO\u2084, AgNO\u2083, NH\u2083<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">4<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Halide Ions: Reducing Agents and Tests<\/p>\n            <p class=\"ols-sub-card-desc\">Halide ions: reducing power with concentrated sulfuric acid, the acidified silver nitrate test and ammonia, and the hydrogen halides with ammonia and water.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n        <\/div>\n    <\/article>\n\n    <article class=\"ols-note-card purple\">\n      <div class=\"ols-note-title\">\n        <div class=\"ols-note-icon\">\u2713<\/div>\n        <h2>How to Use These Pages<\/h2>\n      <\/div>\n\n      <p>Begin with the trends so that every later explanation has a cause. The displacement reactions, the chlorine reactions and the halide reactions are then three sets of redox equations to learn with their colours and observations.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Exam focus:<\/strong> Track chlorine with oxidation numbers in every disproportionation equation, and always say which acid is used to acidify a test and why.<\/p>\n      <\/div>\n    <\/article>\n\n    <section class=\"ols-related-card\">\n      <h2>Related Topic 8 Pages<\/h2>\n      <p>Use these pages to connect Group 7 with the other parts of Topic 8 and with the core practicals.<\/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-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/\">Topic 8A Redox Chemistry<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/\">Topic 8B Groups 1 and 2<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Overview<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-3-concentration-of-hcl-by-titration\/\">CP 3 Concentration of HCl by Titration<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-4-preparation-of-a-standard-solution\/\">CP 4 Preparation of a Standard Solution<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-8-analysis-of-inorganic-and-organic-unknowns\/\">CP 8 Analysis of Inorganic and Organic Unknowns<\/a>\n      <\/div>\n    <\/section>\n\n    <section class=\"ols-attribution-card\">\n      <p><strong>Copyright notice:<\/strong> This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.<\/p>\n    <\/section>\n\n    <script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"WebPage\",\n      \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/#webpage\",\n      \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/\",\n      \"name\": \"Topic 8C Group 7 | Edexcel International A Level Chemistry\",\n      \"description\": \"Edexcel International A Level Chemistry Topic 8C Group 7 landing page: trends in the halogens, halogens as oxidising agents, disproportionation reactions of chlorine, halide ions: reducing agents and tests.\",\n      \"inLanguage\": 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