The size of the nucleus of an atom is about 10 raise to power 15 meter, which basically proposes that it is about 10 raise to power -5 or 1/100,000 we can say of the size of the entire atom. A good comparison of the nucleus to the atom is just like a pea in the midst of a track. The volume of the atom is 2 x 1013 times larger than its nucleus.