Potassium has a bcc structure with nearest neighour distance `4.52 Å`its atomic weight is `39` its density (in kg `m^(-3)`) will be

Options

A. `454`
B. `804`
C. `852`
D. `908`

Answer

d

Explanation

For bcc ,`d = sqrt(3)/(2) a or`
`a= (2d)/(sqrt(3)) = (2xx 4.52)/(1.732) = 5.219 Å = 522` pm
`r = (Z xx M)/(a^(3) N_(0) xx 10^(-30))`
`= (2 xx 39)/((522)^(3) xx (6.023 xx 10^(23)) xx 10^(-30))`
`= 0.91 g//cm^(3) = 910 kg m^(-3)`