Question

Lithium metal crystallizes in a body-centered cubic crystal. If the length of the side of the unit cell of lithium is 351 pm, the atomic radius of lithium will be:

• A. 300.5 pm
• B. 240.8 pm
• C. 151.98 pm
• D. 75.5 pm

Answer 1

The correct option is C 151.98 pm

In case of BCC crystal , $a\times \sqrt{3}=4r$

Hence , atomic radius of lithium,

$r=\frac{a\times \sqrt{3}}{4}$

= $\frac{351\times 1.732}{4}$

= 151.98 pm

So option C is correct.