Give reason for the following :
(i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine, it shows the highest oxidation state of +4
(ii) Transition metals show variable oxidation states.
(iii) Actinoids show irregularities in their electronic configurations.

Explanation

(i) Manganese(Mn) exhibits +7 oxidation state in combination with oxygen (e. g/. `Mn_(2)O_(7)`). This is because of ability of oxygen atom to form multiple bonding (`p pi-d pi)` with the element. However, the highest oxidation state exhibited with fluorin is +4 (e.g., `MnF_(4)`) since no multiple bonding is possible with the element .
(ii) N/A
(iii) This is shown in order to achieve extra stability of the electronic configuration i.e., to acquire `f^(7)` and `f^(14)` electronic configuration in certain elements belonging to actinoid family.