Chemistry - Complete d-block Question with Solution | TestHub

I. ${\mathrm{Fe}}^{2+}=\mathrm{Ar}$
4 unpaired electrons, $\therefore$ Coloured ion, II ${\mathrm{Ni}}^{2+}=\mathrm{Ar}$
2 unpaired electrons, $\therefore$ Coloured ion III. ${\mathrm{Al}}^{3+}=[\mathrm{Ne}]$ Nounpairedelectron in $3\mathrm{d}$, colourless ion.