Question

Discuss the following property with respect to transition elements:

Ionisation energies.

Answer 1

1. Transition elements have high ionisation energies, lying between s- and p-block elements.
2. First ionisation energy generally increases across a series but not regularly.
3. Third series elements have higher ionisation energies due to poor shielding by 4f electrons, leading to stronger nuclear attraction.
4. Ionisation energy influences the stability of oxidation states in compounds; a lower total ionisation energy for forming an ion indicates greater stability.
5. For example, Ni(II) compounds are more stable than Pt(II) compounds because Ni requires less energy to lose two electrons, whereas Pt(IV) compounds are more stable than Ni(IV) due to lower ionisation energy sums for four electrons.