Question

The edge length of a F.C.C. cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is

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

Answer 1

The correct option is D

144 pm

For an ionic substance in F.C.C. arrangement,
$2(r^{+}+r^{-})$ = Edge length
2(110 + $r^{-}$) = 508 ; $r^{-}$ = 144 pm