Question

The ions $O^{2-},F^{-},N{a}^{+},M{g}^{2+}$ and $A{l}^{3+}$ are isoelectronic. Their ionic radii show:

• A. A significant increase from $O^{2-}$ to $A{l}^{3+}$
• B. A significant decrease from $O^{2-}$ to $A{l}^{3+}$
• C. An increase from $O^{2-}$ to $F^{-}$ and then decrease from $N{a}^{+}$ to $A{l}^{3+}$
• D. A decrease from $O^{2-}$ to $F^{-}$ and then increase from $N{a}^{+}$ to $A{l}^{3+}$

Answer 1

The correct option is B A significant decrease from $O^{2-}$ to $A{l}^{3+}$

For isoelectronic species, ionic radii decreases as the number of protons in the ion increases. So, ionic radii decreases from $O^{2-}$ to $A{l}^{3+}$.