🎯 Common Question Types:
- State colour and state of each halogen at room temperature (3 marks)
- Explain why fluorine is more reactive than iodine (3 marks)
- Write the equation for a halogen displacement reaction (2 marks)
- Describe observations in a displacement reaction (2 marks)
- Explain why bromine does not react with sodium chloride solution (2 marks)
📝 Key Command Words:
- Explain: Always link to outer shell electrons and nuclear attraction
- Predict: Use the reactivity order to decide if displacement occurs
- Describe: Give the colour change observed in displacement reactions
- Write: Balance equations — remember halogens are diatomic (Cl₂, Br₂)
⚠️ Common Mistakes to Avoid:
- Saying reactivity increases down Group 7 — it DECREASES
- Writing Cl instead of Cl₂ in equations (halogens are diatomic)
- Confusing halide ions (Cl⁻) with halogen molecules (Cl₂)
- Not explaining WHY reactivity decreases — always link to outer shell distance
This exam tips covers Exam Tips — Halogens within Group 7: Halogens for GCSE Chemistry. Revise Group 7: Halogens in Atomic Structure for GCSE Chemistry with 22 exam-style questions and 21 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 11 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Group 7: Halogens
How many electrons do halogens have in their outer shell?
Explain why chlorine is more reactive than bromine.
Quick recall flashcards
Cl₂ + 2KBr → ?
2KCl + Br₂ (chlorine displaces bromine)
Will Br₂ + NaCl react?
NO — bromine is less reactive than chlorine