Most stable cation in aqueous medium is

The correct order of decreasing second ionisation enthalpy of $Ti(22), V(23), Cr(24)$ and $Mn(25)$ is

Out of $Cu_2Cl_2$ and $CuCl_2$,which is more stable and why?

What is the correct order of spin only magnetic moment (in $BM$) of $Mn^{2+}, Cr^{2+}$ and $V^{2+}$?

Explain the variations in atomic radii of transition elements along the period. The following table provides data for the first transition series:

Element	Sc	Ti	$V$	Cr	Mn	Fe	Co	Ni	Cu	Zn
Metallic Radius $M$ (pm)	$164$	$147$	$135$	$129$	$137$	$126$	$125$	$125$	$128$	$137$

Which forms coloured salts?