Question

Xenon crystallises in the face-centered cubic lattice and the edge of the unit cell is $620$ pm.The nearest neighbor distance and the radius of xenon atom are respectively :

• A. $438.5$ pm, $219.25$ pm
• B. $219.25$ pm, $438.5$ pm
• C. $438.5$ pm, $438.5$ pm
• D. $219.25$ pm, $219.25$ pm

Answer 1

The correct option is A $438.5$ pm, $219.25$ pm

In FCC lattice,
$a=2\sqrt{2}r$
$620=2\sqrt{2}r$
$⟹r=219.25$ pm
And the nearest neighbour distance = $2r=438.5$ pm