Q. Sodium has body-centred packing. Distance between two nearest atoms is $3.7\ \mathring{\mathrm{A}}$. The lattice parameter is
A) $4.8\ \mathring{\mathrm{A}}$
B) $4.3\ \mathring{\mathrm{A}}$
C) $3.9\ \mathring{\mathrm{A}}$
D) $3.3\ \mathring{\mathrm{A}}$
Explanation
(b) Atomic radius for bcc structure is $r = \frac{a\sqrt{3}}{4}$
or $a = \frac{4r}{\sqrt{3}} = \frac{4(3.7/2)}{\sqrt{3}} = \frac{4 \times 1.75}{1.732} = 4.3\mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.