Question

Ionic radii of :

• A. $T{i}^{4+}<M{n}^{7+}$
• B. ${}^{35}C{l}^{-}{<}^{37}C{l}^{-}$
• C. $K^{+}>C{l}^{-}$
• D. $P^{3+}>P^{5+}$

Answer 1

The correct option is D $P^{3+}>P^{5+}$

Larger the positive charge on the ion smaller will be the size of ion for the same element.
For $P^{3+}$, there are $15$ protons for $12$ electrons while for $P^{5+}$ there are $15$ protons for $10$ electrons. Thus, in $P^{5+}$ the valence electrons are more strongly attracted by the nucleus than those of $P^{3+}$. As a result, there is a larger contraction in the size of $P^{5+}$ than that of $P^{3+}$ Hence, $P^{3+}$ is bigger than $P^{5+}$.