Niobium crystallizes in body-centred cubic structure. If the density is `8.55 g cm^(-3)`, calculate the atomic radius of niobium using its atomic mass `93 u`.

Options

A. 200 pm
B. 185 pm
C. 143 pm
D. 129 pm

Answer

C

Explanation

`a^(3)=(ZxxM)/(d xxNo)=(2xx93)/(8.55xx6.022xx10^(23))`
`=36.1xx10^(-24)cm^(3)`
`a=3.3xx10^(-8)cm^(3)`
for bcc
`r=(sqrt(3))/(4)a=(sqrt(3))/(4)xx3.3xx10^(-8)cm=143` pm.