Question

Why do transition metal have higher ionization enthalpy than s block element?

Answer 1

A transition metal’s ionization energy is related to the energies of its d orbitals, its ease of oxidation, and its basicity. In simplest terms, the greater a metal’s ionization energy, the harder it is to pull an electron from it. Thus, metal centers with high ionization energies exhibit low basicity (or nucleophilicity) and are resistant to oxidation.