1. Aluminum has a face centered cubic (fcc) structure with an atomic radius of 0.143 nm and an atomic weight of 26.98 g/mol. (a) Calculate the density of Al from this information. (b) What is the planar density of atoms in the (110) plane (and sketch how they are arranged). 2. The density of niobium is 8.58 g/cm3. It's atomic mass is 92.91 g/mol and its structure is bcc. (a) calculate the lattic parameter and the atomic radius from this information. (b) What is the planar density of atoms in the (110) plane (and sketch how they are arranged).