Question #44331

Consider the following statements regarding the polarizing power and covalent character of metal halides:

\begin{enumerate} \item[\textbf{I.}] The melting point of \ce{ZnCl2} ($290^\circ\text{C}$) is much lower than that of \ce{CaCl2} ($772^\circ\text{C}$) because \ce{Zn^{2+}} has a smaller ionic radius and a pseudo-noble gas configuration ($ns^2 np^6 nd^{10}$), both of which drastically increase its polarizing power compared to \ce{Ca^{2+}}. \item[\textbf{II.}] Despite \ce{Ag+} having a larger ionic radius ($1.15\text{ \AA}$) than \ce{Na+} ($1.02\text{ \AA}$), \ce{AgCl} exhibits greater covalent character than \ce{NaCl}. This is because the $4d^{10}$ electrons in \ce{Ag+} provide poor shielding, resulting in a higher effective nuclear charge ($Z_{\text{eff}}$) and greater polarizing power. \item[\textbf{III.}] \ce{AgF} is highly soluble in water whereas \ce{AgCl} is insoluble. This is because the small size and high electronegativity of \ce{F-} make it highly resistant to polarization by \ce{Ag+}, rendering \ce{AgF} predominantly ionic. \item[\textbf{IV.}] \ce{CuCl} is more ionic and has a higher melting point than \ce{NaCl} because the $3d^{10}$ electrons in \ce{Cu+} perfectly shield the nuclear charge, reducing its polarizing power and preventing electron cloud distortion. \end{enumerate}

Which of the above statements are correct?