Question

An element A (atomic weight $=100$ amu) having bcc structure has unit cell edge length of $400$ pm. Calculate the density of A.

• A. $2.59$ g cm${}^{-3}$
  
• B. $5.188$ g cm${}^{-3}$
  
• C. $10.37$ g cm${}^{-3}$
  
• D. None of the above

Answer 1

The correct option is B $5.188$ g cm${}^{-3}$

$density=\frac{zM}{N_o\times (a\times {10}^{-10}{)}^3}$

for bcc structure z= 2

$d=\frac{2\times 100}{6\times {10}^{23}\times (400\times {10}^{-10}{)}^3}$

$d=5.188{\text{g cm}}^{-3}$

Hence, the correct option is $\text{B}$