Question

Copper crystallizes in a face-centered cubic cell of an ionic substance is $508$ pm. If the radius of the cation is $110$ pm, the radius of an anion in a $pm$ is :

• A. $288$
• B. $144$
• C. $256$
• D. none of these

Answer 1

The correct option is B $144$

For $fcc$ solid, edge length,$a=(r^{+}+r^{-})$

$r^{-}$ radius of anion

$r^{+}$ = radius of cation

$2(110+r^{-})=508$

$220+2r^{-}=508$

$2r^{-}=508-220$

$2r^{-}=288$

$r^{-}=144pm$