Group VII - Halogens
Cambridge IGCSE Chemistry (0620) · Unit 8: The Periodic Table · 14 flashcards
Group VII - Halogens is topic 8.3 in the Cambridge IGCSE Chemistry (0620) syllabus , positioned in Unit 8 — The Periodic Table , alongside Arrangement of elements, Group I - Alkali metals and Group VIII - Noble gases.
This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical). Past papers from 2022 to 2025 show this topic across undefined questions worth 145 marks (around 2.3% of all Chemistry marks in those years).
The deck below contains 14 flashcards — 6 key concepts and 8 identification cards — covering the precise wording mark schemes reward.
What the Cambridge 0620 syllabus says
Official 2026-2028 specThese are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.
- Describe Describe the Group VII halogens, chlorine, bromine and iodine, as diatomic non-metals with general trends down the group, limited to: (a) increasing density (b) decreasing reactivity
- State State the appearance of the halogens at r.t.p. as: (a) chlorine, a pale yellow-green gas (b) bromine, a red-brown liquid (c) iodine, a grey-black solid
- Describe Describe and explain the displacement reactions of halogens with other halide ions
- Predict Predict the properties of other elements in Group VII, given information about the elements
Which ion is formed from iodine?
Iodine forms the iodide ion, I⁻. Iodine gains one electron to achieve a stable octet configuration.
How does the reactivity of Bromine compare to Iodine?
Bromine is more reactive than iodine because it is a stronger oxidising agent. This means bromine more readily accepts electrons.
Describe the general trend of density in Group VII (Halogens) as you go down the group.
The density of halogens increases as you go down the group. This is because the mass of the atoms increases more rapidly than the volume.
Describe the general trend of reactivity in Group VII (Halogens) as you go down the group.
The reactivity of halogens decreases as you go down the group. This is because the outer electrons are further from the nucleus, making it harder to attract electrons during reactions.
What is the appearance of chlorine at room temperature and pressure (r.t.p.)?
Chlorine appears as a pale yellow-green gas at r.t.p.
What is the appearance of bromine at room temperature and pressure (r.t.p.)?
Bromine appears as a red-brown liquid at r.t.p.
What is the appearance of iodine at room temperature and pressure (r.t.p.)?
Iodine appears as a grey-black solid at r.t.p.
Explain, in terms of reactivity, why bromine can displace iodide ions from a solution containing potassium iodide.
Bromine is more reactive than iodine. Therefore, bromine is a stronger oxidising agent than iodine and will displace iodide ions.
Give the formula for the halogen that is at the top of Group VII.
Fluorine's formula is F₂.
What is the name of the halogen that is below iodine in Group VII?
Astatine (At)
Complete the following displacement reaction: Cl₂ + 2KBr →
Cl₂ + 2KBr → 2KCl + Br₂. Chlorine is more reactive than bromine, therefore it will displace bromine.
Write the ionic equation for the reaction between Lead(II) ions and chloride ions to form lead(II) chloride precipitate.
Pb²⁺(aq) + 2Cl⁻(aq) → PbCl₂(s). Ensure correct formulas, balancing, and state symbols are included.
What precipitate is formed when silver nitrate solution is added to a solution containing chloride ions?
Silver chloride (AgCl) is formed. It is a white precipitate.
Which reagent can be used to test for water and what colour change is observed?
Anhydrous cobalt chloride or cobalt chloride paper can be used. It turns pink/blue to pink in the presence of water.
Tips to avoid common mistakes in Group VII - Halogens
- ● Groups are the vertical columns, while periods are the horizontal rows — picture a 'group' of people standing tall, and a 'period' at the end of a horizontal sentence.
- ● Chart the trends for melting point, boiling point, and density side-by-side for Group I and Group VII.
- ● Memorise both Group 1 AND Group 7 density trends, noting the potassium anomaly in Group 1.
- ● Carefully dissect each option; partial correctness doesn't cut it — the whole statement must be true.
- ● Check every clause in the statement. For halogens, know that fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid at room temperature.
More topics in Unit 8 — The Periodic Table
Group VII - Halogens sits alongside these Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 0620 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Related Chemistry guides
Long-read articles that go beyond the deck — cover the whole subject's common mistakes, high-yield content and revision pacing.
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