the following table summarizes the oxidation states of the 3d series elements. Sc Ti V Cr Mn Fe Co Ni Cu + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + At the beginning of the series, + oxidation state is stable but towards the end + oxidation state becomes stable. The number of oxidation states increases with the number of electrons available, and it decreases as the number of paired electrons increases. Hence, the first and last elements show less number of oxidation states and the middle elements with more number of oxidation states.
For example, the first element Sc has only one oxidation state + ; the middle element Mn has six different oxidation states from + to + . The last element Cu shows + and + oxidation states only. The relative stability of different oxidation states of 3d metals is correlated with the extra stability of half filled and fully filled electronic configurations. Example: Mn 3d +