Iron is a transition element. Iron combines with chlorine to form the compounds `FeCl_2` and `FeCl_3`.
(Hint : Oxidation state of chlorine Cl = -1 , Atomic number of Fe = 26)
a) Write down the oxidation states of Fe in `FeCl_2` and `FeCl_3`.
b) Write the subshell electronic configuration of both of the irons in `FeCl_2` and `FeCl_3`.
c) Give reasons for the different oxidation states of Fe.

Explanation

a. +2,+3
`b. Fe^2+ - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 Fe^3+ - 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5`
c. The energy difference between the outermost s subshell and the penultimate is very small.