# Iron rusts when it is exposed to both oxygen and water. Describe what happens to the iron atoms during rusting in terms of oxidation and reduction, and identify which substance is reduced.

> Cambridge International IGCSE Chemistry (0620) — 6.4 Redox · Describe · 4 marks

> Rusting is an example of a redox reaction in which iron is converted to iron(III) oxide.

## Mark scheme (4 marks)

1. Iron atoms lose electrons during rusting
2. Iron is oxidised
3. Oxygen gains electrons
4. Oxygen is the substance that is reduced

## Key terms

- [oxidation](https://www.gradenine.co.uk/glossary/oxidation)
- [reduction](https://www.gradenine.co.uk/glossary/reduction)

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Source: [GradeNine](https://www.gradenine.co.uk/q/iron-rusts-when-it-is-exposed-125c9d09) · Published by Druglandscape Ltd.