Question

Lead metal has a density of `11.34 g//cm^(3)` and crystallizes in a face-centered lattice. Choose the correct alternatives
A. the volume of one unit cell is `1.214 xx 10^(-22) cm^(3)`
B. the volume of one unit cell is `1.214 xx 10^(-19) cm^(3)`
C. the atomic radius of lead is 175 pm
D. the atomic radius of lead is 155.1 pm

Answer 1

Correct Answer - A::C
Density `= (Z xx M)/(N_(A) xx "volume")` ltrbgt so, Volume `= (4 xx 207)/(6.02 xx 10^(23) xx 11.34) = 1.213 xx 10^(-22) cm^(3), 4r = asqrt2`
`r = (4.95 xx 10^(-8) xx sqrt2)/(4) = 175 pm`
Volume `= a^(3) = 1.213 xx 10^(-22)` ltrbgt So, `a = (1.213 xx 10^(-24))^(1//3) rArr a = 4.95 xx 10^(-8) cm`