The electrons which take part in order to exhibit variable oxidation states by transition metals are — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Transition metals exhibit variable oxidation states due to the very small energy gap between their valence ns and penultimate (n - 1)d subshells. Step 2: During chemical bonding, electrons can be lost or shared from both the outer ns and the inner (n - 1)d subshells. Step 3: The outer np orbitals have significantly higher energies and do not participate in variable oxidation state behavior. Consequently, the active electrons are from the ns and (n - 1)d subshells only, matching option (c).