Developing a model for atoms (Geiger and Marsden)
I can describe the structure of atoms, the sub-atomic particles they contain, and developments leading to this model.
Developing a model for atoms (Geiger and Marsden)
I can describe the structure of atoms, the sub-atomic particles they contain, and developments leading to this model.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- The atomic model has changed over time.
- Dalton, Thomson, Rutherford (Geiger and Marsden), Bohr and Chadwick have all suggested atomic models.
- The plum pudding model of the atom & the nuclear model are two important models in the history of the atom's discovery.
- New evidence from the scattering experiment led to a change in the atomic model.
Keywords
Plum pudding model - Model of the atom showing that negative electrons are embedded in a ball of positive charge.
Rutherford's experiment - A stream of positive alpha particles fired through a thin piece of gold foil. This lead to an update of the atomic model, from the plum pudding model to nuclear model.
Nuclear model - Model of the atom with a small positive charge in the centre surrounded by a cloud of orbiting electrons. The atom is mostly empty space. This model is sometimes called the planetary model.
Common misconception
Confusion between the models and the order in which they were conceived. Also, pupils often mix up which subatomic particles are present in each model.
Practise is required listing the key features of each model and the subatomic particles present. A timeline with the key features present helps pupils to understand the process of discovery and how long this can take.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
Exit quiz
6 Questions
Electrons orbit in fixed paths.
Atom is a ball of positive charge with embedded electrons.
Dense nucleus surrounded by orbiting electrons (like planets + sun).
Atoms are indivisible.