Group 7Edexcel GCSE Chemistry: Flashcards

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What are Group 7 elements called?

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What are Group 7 elements called?: Halogens.
What colour and state is chlorine at room temperature?: A pale green/yellow gas.
What colour and state is bromine at room temperature?: A red-brown liquid.
What colour and state is iodine at room temperature?: A grey/purple-black solid.
What is the chemical test for chlorine gas?: It bleaches damp litmus paper, turning it white.
What type of compound forms when a halogen reacts with a metal?: A metal halide (an ionic salt), e.g. sodium chloride.
What happens when a hydrogen halide dissolves in water?: It forms an acidic solution, e.g. hydrogen chloride forms hydrochloric acid.
What is a displacement reaction in Group 7?: A more reactive halogen takes the place of a less reactive halogen in a solution of its halide.
What is the trend in reactivity down Group 7?: Reactivity decreases going down the group (chlorine most reactive, iodine least).
In the reaction Cl2 + 2Br- -> 2Cl- + Br2, which species is reduced and which is oxidised?: Chlorine is reduced (gains electrons); bromide ions are oxidised (lose electrons).
Why does reactivity decrease down Group 7?: Atoms have more shells going down the group, so the outer shell is further from the nucleus and more shielded, making it harder to gain an extra electron.
Predict whether chlorine would displace astatine from a solution of astatide ions.: Yes — chlorine is much more reactive than astatine (below iodine), so it would displace it.