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GCSE Questions: Nuclear Structure

Q4. Atomic models have changed over time.

 

Old atomic model – Atoms are a positive mass with negative electrons fixed in it.

Current atomic model – Atoms are made from protons, neutrons and electrons. Protons and neutrons are in a central nucleus surrounded by a cloud of electrons.

 

(a) Write down two differences between these models.

Any two from:

The old model has no protons

The old model has no neutrons

There is no nucleus in the old model The electrons are in fixed positions in the old model

The positive particles are in a nucleus in the current model

The negative particles/electrons are outside / surround the nucleus in the current model

[2 marks]

(b) Why did the atomic model change?

 

Any two from:

New evidence had been found that suggested the new model

Experiments had been completed and checked supporting the new model

Previous model couldn't explain new observations

[2 marks]

(Total 4 marks)