Question

Sodium metal crystallizes in bcc lattice with edge length of $4.29\mathring{A}$. The radius of sodium atom is:

• A. $2.857\mathring{A}$
• B. $1.601\mathring{A}$
• C. $2.145\mathring{A}$
• D. $1.857\mathring{A}$

Answer 1

The correct option is D $1.857\mathring{A}$

In bcc lattice, atoms touch along the body diagonal, hence:

$\sqrt{3}a=4r$

$r=\frac{\sqrt{3}}{4}\times 4.29=1.857A^o$