Question

The density of Po is 9.4 g/cm3. Showing your full work, calculate the crystal/unit cell parameter (a) of Po

Answer 1

Answer

Polonium crystallises in a simple cubic unit cell

We know the equation of density of a unit cell  

d =(Z.M) / (a³.N_A)

Z= number of atoms per unit cell (= 1 forsimple cubic unit cell)

M= Molar mass in g/mol ( 209g)

N_A = Avogadro constant in per mol ( 6.022*10²³)

a = Edge length

d = Density( 9.4g/cm³)

so from the above equation we can find the edge lengrh since all other parameters are given

a³= Z.M / d.N_A

= (1*209) / (9.4*6.02*10²³)

a³= 3.69*10^-23

a = 3.3*10^-8