Strontium (Sr) has the FCC crystal structure, an atomic radius of 0.215 nm, and an atomic weight of 87.62 g/mol. What is its theoretical density?

Answer:Theoretical density = 2.576g/cm³

Explanation:

Theoretical density p = (A*n) / Vc * Av

A = molecular weight

n = effective number of atoms per unit cell

Vc=Volume of unit cell = a³

Av = Avogadro's constant = 6.02*10²³

Given that A = 87.2g/mol

n = 4 (For FCC crystal structure)

Vc = a³

Where a = 2R√2 and R is the atomic radius

R=0.215

a = 2 * 0.215*√2

a = 0.608nm = 0.608*10^-7 cm

Vc = (0.608*10^-7 cm) ³

Vc=2.25*10^-22 cm³

P = (87.2 * 4) /

(2.25*10^-22) * (6.02*10²³)

P = 2.576g/cm³

Therefore the theoretical density of strontium is 2.576g/cm³