atoms and the periodic table

Question

An atom has a diameter of 5.00 Å and the nucleus of that atom has a diameter of 6.50×10−5 Å. Determine the fraction of the volume of the atom that is taken up by the nucleus. Assume the atom and the nucleus are a sphere.

Answer 1

The volume of a sphere is V = (4 Pi / 3) r³, so the ratio of volumes is:

V_nucleus / V_atom = (D³_nucleus / D³_arom) = (6.5x10^-5)³ / 5³ = 2.197x10^-15