Chemistry - Complete d-block Question with Solution | TestHub

Key Idea Number of oxidation states exhibited by d-block elements is the sum of number of electrons (unpaired) in d-orbitals and number of electrons in s-orbital. (a) $3{\mathrm{d}}^3,4{\mathrm{s}}^2\Rightarrow \mathrm{O}.\mathrm{S}=3+2=5$ (b) $3{\mathrm{d}}^5,4{\mathrm{s}}^1\Rightarrow \mathrm{O}.\mathrm{S}=5+1=6$ (c) $3{\mathrm{d}}^5,4{\mathrm{s}}^2\Rightarrow \mathrm{O}.\mathrm{S}=5+2=7$ (d) $3{\mathrm{d}}^2,4{\mathrm{s}}^2\Rightarrow \mathrm{O}.\mathrm{S}=2+2=4$ Hence, element with $3{\mathrm{d}}^5,4{\mathrm{s}}^2$ configuration exhibits largest number of oxidation states.