Concept:
Transition metals are elements in which the
orbitals are partially filled. Their electronic configuration allows multiple numbers of electrons to participate in bonding, leading to variable oxidation states.
Explanation:
Transition metals exhibit variable oxidation states due to the following reasons:
- Comparable energies of orbitals: The energies of and orbitals are very close, so electrons from both can be lost during bond formation.
- Participation of d-electrons: Unlike s- and p-block elements, transition metals can use d-electrons in addition to outer s-electrons for bonding.
- Incomplete d-subshell: The partially filled d-orbitals allow different numbers of electrons to be removed or shared.
- Stability of multiple configurations: Various oxidation states can be stabilized by ligands or crystal field effects in compounds.
Examples:
- Iron: and
- Copper: and
- Manganese: Shows oxidation states from +2 to +7
Conclusion:
Thus, transition metals show variable oxidation states because both
and
electrons can participate in bonding due to their similar energies.