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प्रश्न
Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
उत्तर
The electronic configuration of Mn2+ is [Ar]18 3d5 while that of Fe2+ is [Ar] 3d6. Since Mn2+ has a half-filled orbit (3d5), which is more stable than the 3d6 orbit of Fe2+, Mn2+ compounds are not easily oxidised to Mn3+ because of very high second ionization enthalpy. In contrast, Fe2+ compounds are easily oxidised to Fe3+ due to lower second ionization enthalpy. This is the reason that Mn2+ compounds are more stable than Fe2+ towards oxidation to their +3 state.
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