Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
Solution and Explanation
Electronic configuration of Mn2+ is [Ar]1818 3d5 .
Electronic configuration of Fe2+ is [Ar]18 3d6 .
It is known that half-filled and fully-filled orbitals are more stable. Therefore, Mn in (+2) state has a stabled 5 configuration. This is the reason Mn2+ shows resistance to oxidation to Mn3+ . Also, Fe2+ has 3d6 configuration and by losing one electron, its configuration changes to a more stable 3d5 configuration. Therefore, Fe2+ easily gets oxidized to Fe+3 oxidation state.
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Concepts Used:
Properties of D Block Elements
- Multiple oxidation states- The oxidation states of d block elements show very few energy gaps; therefore, they exhibit many oxidation states. Also, the energy difference between s and d orbital is very less. Therefore both the electrons are involved in ionic and covalent bond formation, which ultimately leads to multiple oxidation states.
- Formation of complex compounds- Ligands show a binding behavior and can form so many stable complexes with the help of transition metals. This property is mainly due to:
- Availability of vacant d orbitals.
- Comparatively small sizes of metals.
- Hardness- Transition elements are tough and have high densities because of the presence of unpaired electrons.
- Melting and boiling points- Melting and boiling points of transition are very high because of the presence of unpaired electrons and partially filled d orbitals. They form strong bonds and have high melting and boiling points.
- Atomic radii- The atomic and ionic radius of the transition elements decreases as we move from Group 3 to group 6. However, it remains the same between group 7 and group 10, and from group 11 to group 12 increases.
- Ionization enthalpy- The ionization enthalpies of the transition elements are generally on the greater side as compared to the S block elements