Question

Give reasons:

Transition metals show variable oxidation states.

Account for the following:

Transition metals show variable oxidation states.

Explain giving reasons:

Transition elements exhibit variable oxidation states.

Why do transition elements exhibit variable oxidation states?

Answer 1

1. The variable oxidation states of transition elements are due to the participation of ns and (n − 1) d-electrons in bonding. 
2. A lower oxidation state is exhibited when the ns-electrons take part in bonding.
3. Higher oxidation states are exhibited when the (n − 1) d-electrons take part in bonding. 
4. Since there is very little energy difference between these orbitals, both energy levels can be used for bond formation.

Thus, transition elements exhibit variable oxidation states.

Answer 2

1. In transition elements, the 3d and 4s electrons are close in energy and can be lost in different numbers during reactions.
2. The involvement of both (n − 1) d and ns electrons in bonding allows multiple oxidation states.
3. Stability of oxidation states is influenced by half-filled or fully filled d-subshells, leading to preferred oxidation numbers.
4. For example, manganese shows oxidation states from +2 to +7, reflecting this variability.

Hence, transition elements show a wide range of oxidation states because they can lose different numbers of d and s electrons easily.