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# Which of the following statements are incorrect?

(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

$\begin{array}{1 1} \text{Only (2) is incorrect.} \\ \text{(2) and (4) are incorrect} \\ \text{(1), (2) and (3) are incorrect} \\ \text{(1), (3) and (4) are incorrect } \end{array}$

Answer (2) and (4) are incorrect.
Ionic radius of K$^{+}$ is larger than that of Cl$^{-}$ even though they are isoelectronic:
$\quad$ K$^{+}$ is a cation and has a nuclear charge 19. Cl$^{-}$ is an anion with a nuclear charge of 17.
$\quad$ Due to higher nuclear charge, K$^{+}$ is smaller even though both are isoelectronic.
Cations are always larger than the neutral atoms from which they are derived
$\quad$ Positively charged ions are always smaller than the neutral atoms from which they are formed.
$\quad$ As the magnitude of the positive charge increases on isoelectronic ions, their size decreases.