Question

Sodium metal crystallises in a body-centred cubic lattice with cell edge, $a=4.29\stackrel{\circ }{A}$. What is the radius of sodium atom?

Answer 1

In body centered cube, $4r=\sqrt{3}a$

Radius = $\frac{\sqrt{3}}{4}\times 4.29\stackrel{o}{A}=1.857\stackrel{o}{A}$