Question

explain Rutherford's alpha scattering experiment and give its observations and conclusion drawn

Answer 1

Rutherford carried an experiment to explore how the subatomic particles are arranged in an atom which was his alpha particle scattering experiment which led to the discovery of positively charged nucleus in the atom containing protons and neutrons. When the fast moving alpha particles were allowed to strike a very thon gold foil in vacuum, it was found that,
most of the alpha particles pass straight, some were deflected through small angles , some were deflected through large angles while some were completely rebound on hitting the gold foil and turn back.
CONCLUSIONS
Since many particles passed,so there is a lot of empty space in the atom
Deflection of particles shows that there is a centre of positive charge
Rebounds of particles shows that the nucleus is very dense and hard which does not allows the alpha particles to pass through it .
It may help ,...

Answer 2

In his famous experiment, Rutherford bombarded a thin sheet (0.00006 cm thick) of gold foil with alpha (α-) particles in an evacuated chamber. A simplified picture of α-particle scattering by thin gold foil.

The following observations were made on the results obtained.

(i) Most of the α-particle passed through the foil straight without suffering any change in their direction.

(ii) A small fraction of α-particles were deflected through small angles, and a few through larger angles.

What conclusions were derived from the scattering experiment

The following conclusions were drawn from the Rutherford’s scattering experiment.

1. Most of the α- particles passed straight through the foil without suffering any deflection. This shows that most of the space inside the atom is empty or hollow.

2. Some of the α- particles suffered deflection by 90° or even larger angels. For this to happen α- particles (positively charged) must approach a heavy positively charged core inside the atom (Like charges repel each other). This heavy positively charged ‘core’ inside the atom was named as nucleus.

3. Since the number of α- particles which bounced back was very small, hence, the volume occupied by the nucleus is very small as compared to the total volume of the atom.

4. The α- particles have appreciable mass. These are deflected by the nucleus. It means that almost the entire mass of the atom lies at its center, i.e., entire mass of an atom is concentrated inside its nucleus