AQA GCSE Chemistry (8462), Higher tier · Atomic structure and the periodic table › The periodic table
Practise Group 7. 14 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
(a) Write the ionic equation for the reaction of chlorine with bromide ions.[2]
(b) Complete the half equation for chlorine. Cl2 + ....e− → ....Cl−[1]
(c) Which species is oxidised in this reaction? Explain your answer.[2]
(d) Explain why the reactivity of the halogens decreases down Group 7.[3]
Show the answer and mark scheme
(a)Answer: Cl2 + 2Br− → 2Cl− + Br2
Cl2 + Br− → Cl− + Br2 (correct species)
balanced: Cl2 + 2Br− → 2Cl− + Br2
(b)Answer: Cl2 + 2e− → 2Cl−
Cl2 + 2e− → 2Cl−
(c)Answer: Bromide ions, because they lose electrons.
bromide ions / Br−
(because they) lose electrons
(d)Answer: The atoms get larger, so the outer shell is further from the nucleus; there is weaker attraction for an extra electron, so an electron is gained less easily.
atoms get larger / outer shell is further from the nucleus / more shells
(so there is) weaker attraction (from the nucleus) for the electron being gained