Enthalpy of atomisation is the change in enthalpy when one mole of bonds are completely broken to obtain atoms in the gaseous phase. Transition elements have high effective nuclear charge and a large number of valence electrons. Therefore, they form very strong metallic bonds as a result, the enthalpy of atomisation of transition metal is high. Due to the absence of unpaired electrons, the inter-atomic electronic bonding is the weakest in Zn and as a result, it has the least enthalpy of atomisation due to presence of 3 unpaired electrons. Vanadium have the highest atomisation enthalpy.