Question

Why do the transition elements have higher enthalpies of atomisation? In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why ?

Answer 1

Enthalpy of atomisation is the amount of heat required to break the metal lattice to get free atoms. As transition metals contain a large number of unpaired electrons, they have strong interatomic attractions (metallic bonds). Hence, they have high enthalpies of atomisation.

In 3d series, zinc has lowest enthalpy of atomisation as it has no unpaired electron. Hence, interatomic bonding (metal-metal bonding) is the weakest in zinc.