Question

on what basis does rutherford concluded that electron revolve around the nucleus?

Answer 1

Rutherford bombarded a thin gold foil with radioactive rays ( α-particles) and a ZnS screen was placed in back of the gold file so that when the particles strike to the foil some of them get scattered and produced a glow on the ZnS screen.
The phenomena was monitored by a microscope and the observations obtained were:
1. Almost all of the α-particles passed through the metal and remain un deflected.
2. Some of the α-particles deflected through a very small angles.
3. Very few of them deflected through 900 or even larger angle.

So, the conclusions or inferences obtained were:

1. Since, almost all particles passed un deflected so the space inside the atom is empty, and large deflection by some particles show that show existence of positively charged inside the body of atom which repelled the +ve charged α-particles.
The heavily positive charged center is termed as "nucleus"
2.Since, deflection was very few means, that the nucleus takes very small space or volume inside atom.
3. Since, heavy α-particles get deflection means nucleus must have the mass.
On the basis of above conclusions, he found that , the negatively charged electrons are revolving round the nucleus with positive protons in centre.