# Fluorine, chlorine, bromine and iodine are all halogens in Group 7 of the periodic table. A student dissolves chlorine gas in water to produce chlorine water. The chlorine water is described as a good oxidising agent. Explain, in terms of electron transfer, why chlorine acts as an oxidising agent, and state what happens to the chlorine atoms as a result.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 2.2 Group 7 (halogens) · Explain · 4 marks

> Halogens are found in Group 7 of the periodic table. They gain an electron to form halide ions with a 1− charge. An oxidising agent is a species which brings about oxidation by gaining electrons and is itself reduced.

## Mark scheme (4 marks)

1. Chlorine gains electrons (from another species)
2. Chlorine is reduced / chlorine atoms become chloride ions (Cl⁻)
3. The other substance / species loses electrons and is therefore oxidised
4. An oxidising agent is itself reduced / chlorine acts as the oxidising agent because it is the species that gains the electrons

## Key terms

- [oxidising agent](https://www.gradenine.co.uk/glossary/oxidising-agent)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/fluorine-chlorine-bromine-and-iodine-are-7a9569ac) · Published by Druglandscape Ltd.