# Bohr developed a modification of Rutherford's nuclear atomic model. Explain how Bohr's model differed from Rutherford's model, and explain why scientists accepted Bohr's model as an improvement.

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

> In the early twentieth century, several scientists proposed different models of the atom. Each new model was developed to better explain experimental evidence that earlier models could not account for.

## Mark scheme (4 marks)

1. Rutherford's model placed electrons orbiting the nucleus but did not specify fixed positions/energy levels for the electrons.
2. Bohr proposed that electrons exist in shells (orbits) of fixed energy around the nucleus.
3. Bohr's model better explained existing experimental observations/evidence that Rutherford's model could not explain.
4. Scientific models are accepted/updated when new evidence supports them, showing the development of scientific understanding over time.

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/bohr-developed-a-modification-of-rutherford-s-b9bffa29) · Published by Druglandscape Ltd.