Nickel has a face-centered cubic structure and has a density of 8.90 g/cm3. what is its atomic radius?

Density = (mass/volume)

Mass = # atoms (in unit cell) x (mol / 6.022 x 10^23 atoms) x (58.69 g/mol)

The last number is the atomic mass of nickel

The number of atoms = 8 (1/8) + 6 (1/2) = 4

The volume (of the entire unit cell) = side^3 = (r x 8^ (1/2)) ^3

6.84 g/cm3 = [4 atoms x (mol / 6.022 x 10^23 atoms) x (58.69 g/mol) ] / [r x 8^ (1/2) ]^3

r = 1.36 x 10^-8 cm