The document provides solutions to two tutorial problems on atomic structure: 1) It derives expressions for the atomic packing factor (APF) of face-centered cubic (FCC) and body-centered cubic (BCC) solids, showing the APF is 74% for FCC and 68% for BCC. 2) It estimates the density of face-centered cubic copper to be 8.887x103 g/m3 based on the number of copper atoms in the FCC unit cell, copper's atomic weight, and Avogadro's number.