Self-Assessment Questions: Module 2.1 Crystalline structures
Problem 1
Lead, Pb , is used in solders and as radiation shield. It adopts the face centered cubic unit structure with each of the atom having a diameter of 0.35 nanometer. Find the theoretical density of lead if the molecular weight of this metal is \( 207.2 \mathrm{~g} / \mathrm{mol} \).
Problem 2
Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. It has a density of 16.4 grams per cubic centimeter and a molecular weight of \( 180.948 \mathrm{~g} / \mathrm{mol} \). What is the atomic radius of Ta if it adopts the body centered cubic unit structure.
Problem 3
Silver is a metal commonly used in jewelry and photography. It crystallizes with a FCC unit cell 0.407 nm on an edge. What is the theoretical density of silver in \( \mathrm{g} / \mathrm{cm}^{3} \) if its atomic weight is 107.87 \( \mathrm{g} / \mathrm{mol} \) ?