Question

Sodium metal crystallises in a body centered cubic lattice with a unit cell edge of 4.29 $\stackrel{\circ }{A}$. The radius of sodium atom is approximately:

• A. 1.86$\stackrel{\circ }{A}$
• B. 3.22$\stackrel{\circ }{A}$
• C. 5.72$\stackrel{\circ }{A}$
• D. 0.93$\stackrel{\circ }{A}$

Answer 1

The correct option is A 1.86$\stackrel{\circ }{A}$

Since it is a body centered cubic, we can use the following formula:

$r_{N{a}^{+}}=\frac{\sqrt{3}}{4}\times a$ = 1.86$\stackrel{\circ }{A}$