Question

Why is the enthalpy of atomisation of zinc the lowest?

Answer 1

The enthalpy of atomization is that the enthalpy change that accompanies the entire separation of all atoms during a chemical substance. this is often often represented by the symbol ΔₐₜH or ΔHₐₜ. All bonds within the compound are broken atomization and none are formed, so enthalpies of atomization are always positive.

Complete answer:
The electronic configuration of zinc is $(Ar)3{d^{10}}4{s^2}$. This element features a completely filled d-orbital and a totally filled 4s orbital also . Therefore, it is often understood that the metallic bonds formed by this element are going to be relatively weak (due to the absence of unpaired electrons). In fact, most other transition elements have a minimum of one unpaired electron and may form relatively strong metallic bonds. The enthalpy of atomization of zinc is the lowest as a consequence of this weak metallic bonding.
The electronic configuration of zinc is $(Ar)3{d^{10}}4{s^2}$. This element features a completely filled d-orbital and a totally filled 4s orbital also . The enthalpy of atomization of zinc is the lowest as a consequence of this weak metallic bonding.
Due to the absence of unpaired electrons in ns and (n–1) d shells, the interatomic electronic bonding is the weakest in zinc. Consequently, zinc has the smallest amount of enthalpy of atomisation within the 3d series of transition elements.
For example: atomization of methane molecules. For diatomic molecules, enthalpy of atomization is adequate to the enthalpy of bond dissociation.

Note:
Standard enthalpy of atomization is the enthalpy change that happens when one mole of a sample is dissociated into its atoms under standard conditions of 298.15 K temperature and 1 bar of pressure.