Problem 3.1 (5 pts.) What is the difference between atomic structure and crystal structure? Problem 3.2 (10 pts.) If the atomic radius of aluminum is 0.143 nm, calculate the volume of its unit cell in cubic meters. Problem 3.9 (10 pts.) Calculate the radius of a vanadium atom, given that V has a BCC crystal structure, a density of 5.96 g/cm3, and an atomic weight of 50.9 g/mol. Problem 3.11 (10 pts.) Zirconium has an HCP crystal structure and a density of 6.51 g/cm3. (a) What is the volume of its unit cell in cubic meters? Problem 3.13 (10 pts.) Rhodium has an atomic radius of 0.1345 nm and a density of 12.41 g/cm3. Determine whether it has an FCC or BCC crystal structure. Problem 3.13 (5 pts.) Explain why the properties of polycrystalline materials are most often isotropic.