Beryllium has a hexagonal crystal structure with a0 = 0.22858 nm and c0 = 0.35842 nm. The atomic radius is 0.1143 nm, the density is 1.848 g/cm3, and the atomic weight is 9.01 g/mol. Determine
(a) The number of atoms in each unit cell; and
(b) The packing factor in the unit cell.