# Describe how scientists' understanding of atomic structure changed from Dalton's model to Rutherford's nuclear model, including the experimental evidence that led to this change.

> OCR GCSE Chemistry A: Gateway Science (J248) — C1.2 Atomic structure · Describe · 4 marks

> Our understanding of atomic structure has developed over time as new experimental evidence became available. Scientists including Dalton, Thomson, and Rutherford each proposed different models of the atom.

## Mark scheme (4 marks)

1. Dalton described atoms as solid spheres that could not be divided / split
2. Thomson's plum pudding model proposed the atom was a positively charged sphere with negatively charged electrons embedded in it / dotted through it
3. Geiger and Marsden fired alpha particles at a thin gold foil and found most passed straight through but some were deflected more than expected / back
4. Rutherford concluded the atom has a small, positively charged nucleus surrounded by mostly empty space with electrons orbiting it

## Key terms

- [atomic structure](https://www.gradenine.co.uk/glossary/atomic-structure)
- [nuclear model](https://www.gradenine.co.uk/glossary/nuclear-model)

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-how-scientists-understanding-of-atomic-27a9deae) · Published by Druglandscape Ltd.