Answer:
1.7700×10^-22 g
Explanation:
A face-centered-cubic cell contains 4 atoms, so the volume per atom is ...
(389.80×10^-12 m)³/(4 atoms) ≈ 1.4725×10^-29 m³
Then the mass of 1 atom is ...
(12020 kg/m³)(1.4725×10^-29 m³) ≈ 1.76995×10^-25 kg
≈ 1.7700×10^-22 g
_____
Additional comment
That is the approximate mass of a Palladium atom.
