Question

Sodium atom crystallizes in the body centred cubic lattice with cell edge, $a$ equal to $4.29A^o$. The radius of the sodium atom is:

• A. $18.6A^o$
• B. $1.86A^o$
• C. $186$ nm
• D. $1860$ pm

Answer 1

Answer: (B)

$1.86A^o$

The relation between radius of the atom and the side of the unit cell in body centered cubic lattice is as follows:

$4r=\sqrt{3}a$ $⟹\frac{4r}{\sqrt{3}}=a$, where $a$ is the side and $r$ is the radius.

$r=\frac{(4.29\times \sqrt{3})}{4}=1.86A^o$

Option B is correct.