(1) Na$^{+}$, Mg$^{2+}$ and Al$^{3+}$ are all isoelectronic
(2) Ionic radius of K$^{+}$ is larger than that of Cl$^{-}$ even though they are isoelectronic
(3) Anions are always larger than the neutral atoms from which they are derived
(4) Cations are always larger than the neutral atoms from which they are derived
$\begin{array}{1 1} \text{Only (2) is incorrect.} \\ \text{(2) and (4) are incorrect} \\ \text{(1), (2) and (3) are incorrect} \\ \text{(1), (3) and (4) are incorrect } \end{array} $
