# Explain how the results of the alpha particle scattering experiment led scientists to conclude that atoms contain a nucleus.

> Edexcel GCSE Chemistry (1CH0) — 1.3 Atomic structure · Explain · 4 marks

> In the early 1900s, Ernest Rutherford and his colleagues fired positively charged alpha particles at a thin sheet of gold foil and observed where the particles went after hitting the foil. Most passed straight through, some were deflected at small angles, and a very small number bounced back almost the way they came.

## Mark scheme (4 marks)

1. Most alpha particles passed straight through, showing that most of the atom is empty space
2. Some alpha particles were deflected / changed direction, showing the nucleus is positively charged
3. A very small number bounced back / were deflected through large angles, showing the nucleus is very small
4. The nucleus contains most of the mass of the atom / the nucleus is dense

## Key terms

- [alpha particle scattering experiment](https://www.gradenine.co.uk/glossary/alpha-particle-scattering-experiment)
- [nucleus](https://www.gradenine.co.uk/glossary/nucleus)

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-results-of-the-4b5b520a) · Published by Druglandscape Ltd.