# Radioactive materials undergo radioactive decay, emitting nuclear radiation. Explain what is meant by the term 'radioactive decay' and describe the changes that occur in the nucleus of an atom when it emits an alpha particle and when it emits a beta particle.

> Eduqas A-Level Physics — 6.1 Radioactivity · Explain · 5 marks

## Mark scheme (5 marks)

1. Radioactive decay is the spontaneous / random emission of nuclear radiation from an unstable nucleus
2. When an alpha particle is emitted, the mass number of the nucleus decreases by 4
3. When an alpha particle is emitted, the atomic / proton number decreases by 2
4. When a beta particle is emitted, the atomic / proton number increases by 1
5. When a beta particle is emitted, the mass number stays the same / does not change

## Key terms

- [radioactive decay](https://www.gradenine.co.uk/glossary/radioactive-decay)
- [alpha particle](https://www.gradenine.co.uk/glossary/alpha-particle)
- [beta particle](https://www.gradenine.co.uk/glossary/beta-particle)

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/radioactive-materials-undergo-radioactive-decay-emitting-bfc25e66) · Published by Druglandscape Ltd.