Question

From the fact that the length of the side of a unit cell of lithium is 351 pm. Calculate its atomic radius. Lithium forms body centred cubic crystals.

• A. 152.69 pm
• B. 62.71 pm
• C. 151.98 pm
• D. 54.61 pm

Answer 1

Answer: (C)

151.98 pm

Answer 2

In (bcc) crystals, atoms touch each other along the cross diagonal.

Hence, Atomic radius $( R ) = \frac { a \sqrt { 3 } } { 4 }$

$= 351 \times \frac{\sqrt{3}}{4} = 151.98pm$