Which of the following transition metal cations has the maximum number of unpaired electrons?

Explain giving reasons:
$(i)$ Transition metals and many of their compounds show paramagnetic behaviour.
$(ii)$ The enthalpies of atomisation of the transition metals are high.
$(iii)$ The transition metals generally form coloured compounds.
$(iv)$ Transition metals and their many compounds act as good catalysts.

Transition elements exhibit variable oxidation states because they lose electrons from which of the following orbitals?

$A$ copper salt is isomorphic with $ZnSO_4$. The salt will be:

Which of the following ions is coloured?

$A$ chloro compound of vanadium has a spin-only magnetic moment of $1.73 \ BM$. This vanadium chloride has the formula: