Why +3 oxidation state of Fe (Z = 26) is more stable than its +2 oxidation state ?

Why is + 2 oxidation state of manganese (Z=25) more stable than its + 3 oxidation state ?

Account for the following: The +2 oxidation state of lead is more stable than +2 oxidation state of Tin.

The stable oxidation state of Ce (Z = 58) is

The + 1 oxidation state of thallium is more stable than its + 3 state. Why ?

The oxidation state of P in (H_3PO_2) is

Why is + 4 oxidation state of titanium more stable than its +3 state? (Z = 22)

Fe^(3+) is more stable than Fe^(2+) . Explain.

STATEMENT-1 : MnO_(2) can act as an oxidizing agent as well as reducing agent. STATEMENT-2 : Oxidation state of MnO_(2) lies between highest and lowest oxidation state.