# Explain what happens to the arrangement and movement of particles when a solid is heated until it melts and then heated further until it boils.

> OCR GCSE Chemistry A: Gateway Science (J248) — C1.1 The particle model · Explain · 4 marks

> The particle model represents the particles in the three states of matter as small solid spheres. Melting and boiling are examples of physical changes.

## Mark scheme (4 marks)

1. In a solid, particles are held in a regular arrangement / fixed positions
2. On melting, particles gain energy and move / break free from their fixed positions so they can move past each other (random arrangement, close together)
3. On boiling, particles gain more energy and overcome the forces holding them together / move faster
4. In the gas, particles are relatively spread out / far apart and move randomly in all directions

## Key terms

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

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](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/explain-what-happens-to-the-arrangement-8e21eca9) · Published by Druglandscape Ltd.