Question

How do you know that nucleus is very small as compared to size of an atom?

Answer 1

The nucleus of an atom is about 10-15m in size; this means it is about 10-5(or 1/100,000) of the size of the wholeatom. A good comparison of thenucleus to the atom is like a pea in the middle of a racetrack. (10-15 m is typical for the smaller nuclei; larger ones go up to about 10 times that.

Answer 2

because in experiment of Rutherford atomic model many alpha rays passed straight through the gold foil without any deflection that is why he said that nucleus is very small as compared to the size of an atom