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SQA National 5 Chemistry Development of the atom

Development of the atom

This page covers the following topics:

1. The nuclear model

Ernest Rutherford used the results from the particle scattering experiment to propose the nuclear model describing a central positively charged nucleus with orbiting electrons. Niels Bohr described that electrons were occupying energy shells in this way surrounding the nucleus. In 1932 James Chadwick discovered the neutron which suggested that the nucleus consists of protons and neutrons. These discoveries led to the theory of the nuclear model, which is the model of the atom we know today, nucleus containing protons and neutrons surrounded by electrons in energy shells.

The nuclear model

1

Draw a diagram representing the nuclear model including subatomic particles.

Draw a diagram representing the nuclear model including subatomic particles.

2

Where are the electrons in the atom?

Where are the electrons in the atom?

3

Which scientist provided evidence to support the nuclear model, specifically the composition of the nucleus?

Which scientist provided evidence to support the nuclear model, specifically the composition of the nucleus?

4

Describe how and why the atomic model has changed over time.

Describe how and why the atomic model has changed over time.

5

Where is the majority of mass in an atom according to the nuclear model?

Where is the majority of mass in an atom according to the nuclear model?

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