Question

Account for the following 

The enthalpy of atomisation is lowest for Zn in 3d series of the transition elements.

Answer 1

The extent of metallic bonding an element undergoes, decides the enthalpy of atomisation. The more extensive the metallic bonding of an element, the more will be its enthalpy of atomisation. In all transition metals (except Zn, electronic configuration: 3d¹⁰ 4s²), there are some unpaired electrons that account for their stronger metallic bonding. Due to the absence of these unpaired electrons, the inter-atomic electronic bonding is the weakest in Zn and as a result, it has the least enthalpy of atomisation.