Question

Describe the variable oxidation state of 3d series elements.

Answer 1

1. The first transition metal Scandium exhibits only a +3 oxidation state, but all other transition elements exhibit variable oxidation states by losing electrons from (n-l)d orbital and ns orbital as the energy difference between them is very small.

2. At the beginning of the 3d series, the +3 oxidation state is stable but towards the end +2 oxidation state becomes stable.

3. The number of oxidation states increases with the number of electrons available, and it decreases as the number of paired electrons increases. For example, in the 3d series, the first element Sc has only one oxidation state +3 the middle element Mn has six different oxidation states from +2 to +7. The last element Cu shows +1 and +2 oxidation states only.

4. Mn²⁺ (3d⁵) is more stable than Mn⁴⁺ (3d³) is due to a half-filled stable configuration.