Question

Copper crystallizes in fcc with a unit cell length of 361 pm. What is the radius of copper atoms?

• A. 157 pm
• B. 181 pm
• C. 127 pm
• D. 108 pm

Answer 1

Answer: (C)

127 pm

Answer 2

For fcc,

$r = \frac{\sqrt{2}}{4}a = \frac{\sqrt{2}}{4} \times 361 = \frac{1.414 \times 361}{4} = 127pm$