What may be the stable oxidation state of the transition elements with the following d electron configurations in the ground state of their atoms : `3d^(3), 3d^(5), 3d^(8) & 3d^(4)` ?

Explanation

For the first row transition elements the oxidation states of reasonable stability correspond in value to the sum of the 3d - and 4s - electrons upto Mn. But towards the end of the series only 4s - electrons (except for Cu) take part in bonding. The ground state valence shell configuration and hence, stable oxidation states of the given atoms will be as follows :
`|{:("Given","Ground state","Stable oxidation"),("configuration","configuration","state"),(3d^(3),3d^(3)4s^(2),+5),(3d^(5),3d^(5)4s^(1),+6),(3d^(5),3d^(5)4s^(2),+7),(3d^(8),3d^(8)4s^(2),+2 "(only 4s - electrons participate)"),(3d^(4),"There is no " d^(4) "configuration",-):}|`