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

Options

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

Answer

B

Explanation

In fcc unit cell, (a=361 pm)
`4r=sqrt(3)a`
`r=(sqrt(3))/(4)a`
`=(sqrt(3))/(4)xx361`
`r=127pm`