Describe Rutherford's Alpha Particle experiment

In 1911 Rutherford made and experiment to study about the structure of atom. In this experiment the α-particles from ₈₃Bi²¹⁴ (a radioactive source) contained in a lead cavity are collinated into a narrow beam with the help of a lead plate having a narrow slit the narrow beam of α-particles then falls on a thin gold foil (about 2.1 x 10^-10 m thick). The α-particles scattered in different directions.The whole apparatus was arranged inside a vaccum chamber toprevent the scattering of α-particles from air molecules. The experimental observations led Rutherford to the following conclusions-

(i) Since most of the α-particles passed undiviated, than atom has a lot of empty space in it. 

(ii) Since the fast and the heavy α-particle could be deflected through even 180°, the whole of + ve charge and partcially the entire mass of the atom was confined to an extremely small central core. 

It was called nucleus. 

Since 1 in about 8000 α-particles in deflected through 180°, the size of the nucleus is about 1/10,000 th of the size of the atom.

(iii) The scattering of different α-particles through different angles on the nuclear model of the atom as below.

The α-particles such as a and a',which pass through the atom at a large distance from the nucleus experiences a small electrostatic force of repulsion due to the nucleus and hence undergo a very small deflection. The α-particles b and b¹ which pass through the atom at a close distance from the nucleus suffer a large deflection.The α-particles such as C, which travels towards the nucleus directly, shows down as it moves and ultimately comes to rest and than after being deflected through 180°, retraces it path.