Question

Describe Rutherford's scattering experiment.

Answer 1

Rutherford's scattering experiment:

1. Rutherford conducted a gold foil experiment where he bombarded a very thin gold foil with alpha particles.
2. The thickness of the gold foil is $~100\mathrm{nm}$ with alpha particles in an evacuated chamber.
3. Around the foil, a circular fluorescent screen is coated with zinc sulphide ($\mathrm{ZnS}$).
4. When the alpha particles were passed through a slit in a lead plate, they struck the screen and produced a flash of light.
5. Rutheford explained the sub-atomic particles would deflect the alpha particles.

Observations of scattering experiment:

1. Most of the alpha particles passed straight without any deflection.
2. A small fraction of the alpha particles were deflected at small angles, while few were deflected at large angles.
3. A very few alpha particles were bounced back on the gold foil.

Results of scattering experiment:

1. Most of the space in an atom is empty because most of the positively charged alpha particles passed through the foil are undeflected.
2. A few positively charged alpha particles are deflected due to a heavy positive centre in the atom.
3. A very few alpha particles are bounced back because the nucleus is very hard and dense.
4. The volume occupied by the nucleus is negligibly small.