Question

2) Why do transition elements show variable
oxidation states
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Answer 1

Transition elements show variable state oxidation in their compounds because there is a very small energy difference in between (n-1)d and ns orbitals. As a result, electrons of (n-1)d orbitals as well as ns-orbitals take part in bond formation.

Answer 2

These elements show variable oxidation state because their valence electrons in two different sets of orbitals, that is (n-1)d and ns. The energy difference between these orbitals is very less, so both the energy levels can be used for bond formation. Thus, transition elements have variable oxidation states