Question

(a) Give the observations as well as inferences of Rutherford's scattering experiment for deter­mining the structure of an atom.

(b) On the basis of above experiment write the main features of atomic model.

Answer 1

(a) Rutherford's scattering experiment:

1. Rutherford carried out gold foil experiment where he bombarded a very thin gold foil with positively charged alpha particles.
2. Based on the alpha particles scattering experiment, Rutherford has proposed the nuclear model of an atom.

Observations and inferences of Rutherford's experiment:

1. Most of the alpha particles passed through the foil undeflected. This shows that most space inside the atom is empty.
2. Some alpha particles got deflected at different angles. This is because the positively charged nucleus repelled positively charged alpha particles.
3. Very few alpha particles bounced back after hitting the gold foil. This shows that the nucleus is very tiny and dense.

(b) Main features of Rutherford's atomic model:

1. The positive charge of the atom and mass of the atom was concentrated in a very small region in the center of atom called nucleus.
2. The nucleus is the densest part of an atom.
3. The nucleus consists of protons and neutrons called nucleons.
4. The size of the nucleus is extremely small as compared to the size of an atom.
5. The nucleus is surrounded by electrons.
6. The atom on the whole is electrically neutral.