To understand the implications of Rutherford’s a-particle scattering experiment:
Activity: Let a child stand in front of a wall with his eyes closed. Let him throw stones at the wall from a distance. He will hear sound for each strike of stone on the wall. This is like a nucleus of the atom. But if a blind-folded child has to throw stones at a barbed-wire fence, most of the stones would not hit the fencing and no sound would be heard.
This is because there are lots of gap in the fence which allows the stone to pass through them. This is like empty space in an atom through which a-particles will pass through.
Based on the above activity and similar reasoning Rutherford concluded the a-particle scattering experiment as:
(1) Most of the space inside the atom is empty as a-particles passed through the foil.
(2) Very few particles deflected from their path, this show that positive charge occupies less space.
(3) A very small fraction of a-particles are deflected by 180°, this shows that all the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.