Question

The ionic radius of $N{a}^{+}$ ion is $1.02\stackrel{\circ }{A}$. The ionic radii $in\stackrel{\circ }{A}$ of $M{g}^{2+}$ and $A{l}^{3+}$. respectively, are

• A. $0.71$ and $0.54$
• B. $1.05$ and $0.99$
• C. $0.68$ and $0.72$
• D. $0.85$ and $0.99$

Answer 1

The correct option is A $0.71$ and $0.54$

Ionic radius of isoeletronic ions of the same period decreases due to increased nucleus charge.
Order of ionic size $N{a}^{+}>M{g}^{2+}>A{l}^{3+}$
Hence, option (a) is the correct.