Question

What is the oxidation state of iron in the following: FeO Fe2O3 Fe2O4

Answer 1

Electron Configuratio of Iron is:

1s²2s²2p⁶3s²3p⁶4s²3d⁶

According to theory Iron has 2 valence electrons in 4s², which means it must have 2 valency and should be available in +2 oxidation state. But it is a transition metal, which means 3d⁶ also acts a valence shell and these 6 electrons are also available for bonding

FeO: It is made by combination of Fe²⁺and O^2-. Hence, oxidation state of Iron is +2 which is achieved by losing two 4s² electrons.

Oxidation state in Fe₂O₃ is +3 which is achieved by losing two 4s² electrons and one 3d⁶ electron

Similarly, oxidation state in Fe₂O₄ is +4 which is achieved by losing two 4s² electrons and two 3d⁶ electron