1 Jan 1911 Jahr - Rutherford Model of the Atom

Beschreibung:

The Geiger-Marsden gold foil experiment saw that for alpha particles fired at a gold foil, 99% passed through undeflected, while some deflected at large angles and a small number reflected back. Such observations could not be explained by Thomson's model, as charge is distributed evenly and so 100% of alpha particles should pass through undeflected.

Thus, Rutherford proposed the existence of a concentrated positively charged nucleus at the centre of the of atom: this allowed alpha particles to be deflected. His model of the atom then follows:
An atom consists mostly of empty space and a tiny positively charged nucleus carrying almost all of its mass. Electrons which have negligible mass surround the nucleus. The electrons revolve around the nucleus in much the same way as planets orbit around the Sun.

Limitations: Could not answer the following questions:
- What is the nucleus made up of?
- What kept the electrons from being attracted into the positive nucleus?
- How are electrons arranged around the nucleus?

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