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

Explanation

`3d^(3)4s^(2)=+5" "3d^(5)4s^(1)=+6`
`3d^(5)4s^(2)=+2,+7" "3d^(8)4s^(2)=+2`
`3d^(4)4s^(2)` or `3d^(5)4s^(1)=+3` and +6