Why do transition metals like vanadium show a range of oxidation states?
The 3d transition elements show a formidable multiplicity of oxidation states, although a pattern can be discerned and explained. It is because of the close similarity in energy of the 4s and 3d electrons that they exhibit a variety of oxidation states. Comapre this with the s block elements (Group I and Group II). These are limited to oxidation numbers of +1 and + 2 respectively because, once the s-electrons are removed the loss of p electrons is prohibited in chemical reactions by the greater energies involved.
