The nucleus of the hydrogen atom has a radius of about 1.2 x 10-15 m. The electron is at a distance of about 6.3 x 10-11 m from the nucleus. Assuming the hydrogen atom is a sphere with a radius of 6.3 x 10-11 m, find (a) the volume of the atom, (b) the volume of the nucleus, and (c) the percentage of the volume of the atom that is occupied by the nucleus.