The d and f Block elements – Solutions
1. Why are Mn2+ compounds more stable than Fe2+ compounds towards oxidation to the +3 state?
Mn2+ compounds are more stable than Fe2+ compounds towards oxidation to their + 3 state, due to half filled d-orbitals in Mn2+ , while Fe2+ gains half filled d-orbitals by losing one electron by getting oxidised to Fe3+ . Hence , Mn2+ is not oxidised easily to Mn3+ .
Fe2+ Fe3+ + e−
3d6 → 3d5
Mn2+ → Mn3+ + e−
3d5 → 3d4