10. Lithium crystallizes in a bcc structure with an edge length of 3.509 Å. Calculate its density. What is the approximate metallic radius of lithium in picometers? -

Question 2. HfO2 has the CaF2 crystal structure. Calculate the density of HfO2 in kg/m³ if the ionic radii are Hf* = 0.083 nm and O²- = 0.132 nm.

Sodium chloride (NaCl) has the rock salt crystal structure and a density of 2.17 g/cm³. The atomic weights of sodium and chlorine are 22.99 g/mol and 35.45 g/mol, respectively. (a) Determine the unit cell edge length. nm (b) Determine the unit cell edge length from the radii in the table below assuming that the Nat and Cl- ions just touch each other along the edges. nm Cation Mg2+ Fe2+ Na+ Ionic Radius (nm) 0.072 0.077 0.102 Anion Ionic Radius (nm) CI- 0²- 0.181 0.140

Molybdenum, a BCC metal has an atomic radius of 0.136 nm. (a) Calculate the d-spacing for the (211) plane.