Question

Copper crystallizes in a face-centered cubic lattice with a unit cell length of $361\text{pm}$. What is the radius of copper atoms in $\text{pm}$?

• A. $157$
• B. $181$
• C. $108$
• D. $128$

Answer 1

The correct option is D $128$

Since $Cu$ crystallizes in a face-centered cubic lattice,
Atomic radius,
$r=\frac{a}{2\sqrt{2}}$
Where, a = Edge length = 361 pm
$r=\frac{361}{2\sqrt{2}}$
$=127.6\approx 128\text{pm}$