Question

The edge length of a face centered cubic cell of an ionic substance is $508$ pm. If the radius of the cation is $110$ pm, the radius (in pm) of the anion is:

• A. $288$
• B. $398$
• C. $618$
• D. $144$

Answer 1

The correct option is D $144$

For an ionic substance in FCC arrangement,

$2\times (r^{+}+r^{-})=$ Edge length

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

$r^{-}=144$ pm

Hence the correct option is D.