Which of the following ions is colourless in solution?

Arrange the following ions in the increasing order of their magnetic moments: $(i) \, V^{4+}$,$(ii) \, Mn^{4+}$,$(iii) \, Fe^{3+}$,$(iv) \, Ni^{2+}$. $[V = 23, Mn = 25, Fe = 26, Ni = 28]$

The placement of $Zn,$ $Cd,$ and $Hg$ along with $d-$block elements is not considered proper because:

The coinage metals are

The electronic configuration $3d^{10}4s^0$ is exhibited by which of the following ions?

Which one of the following sets correctly represents the increase in the paramagnetic property of the ions?