Which of the following statements are correct about $Zn,\,Cd$ and $Hg$ ?

$(I)$ they exhibit high enthalpies of atomisation as the $d-$ subshell is full

$(II)$ $zn$ and $Cd$ do not show variable oxidation states while $Hg$ shows $+ I$ and $+ II$

$(III)$ Compound of $Zn,\,Cd$ and $Hg$, are paramagnetic in nature

$(IV)$ $Zn,\,Cd$ and $Hg$ are called soft metals

The transition element that has lowest enthalpy of atomisation is

If spin only magnetic moment of $VCl_X$ is $1.73\,BM$ then correct formula is

When $Cu^{2+}$ ion is treated with $KI$, a white precipitate is formed. Explain the reaction with the help of chemical equation.

'Spin only' magnetic moment is same for which of the following ions?

$A$. $\mathrm{Ti}^{3+}$   $B$. $\mathrm{Cr}^{2+}$   $C$. $\mathrm{Mn}^{2+}$   $D$.$\mathrm{Fe}^{2+}$  $E$. $\mathrm{Sc}^{3+}$

Choose the most appropriate answer from the options given below.