Question

Potassium crystallizes in a body-centered cubic lattice with edge length aequal to 5.2 $\mathring{A}$ , what is the calculated density (in g cm${}^{-3}$) of crystalline potassium ?

• A. $2.2$
• B. $1.9$
• C. $0.92$
• D. None of the above

Answer 1

Answer: (C)

$0.92$

As we know, density $=d=\frac{nM}{V{N}_o}$
Here, $n=2$

$d=\frac{2\times 39}{\left(a{)}^3\right(N_o)}=0.92$ g cm${}^{-3}$