Question

Sodium has a bcc structure with nearest neighbour distance of 365.9 pm. Calculate its density (atomic mass of sodium = 23)

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

$d=\frac{\sqrt{3}}{2}$ a

$\Rightarrow$ $d=\frac{2}{\sqrt{3}}$ d = $\frac{2}{1.732}\times 365.9$ =422.5pm

For bcc,Z=2

$\int$= $\frac{z\times m}{a^3\times N_A\times {10}^{-30}}$

= $\frac{2\times 23}{{422.5}^3\times 6.02\times {10}^{23}\times {10}^{-30}}$= 1.51g/$c{m}^3$