Q. Assertion : In the series to , the enthalpy of atomisation of zinc is the lowest.
Reason : Zinc has greater number of unpaired electrons.

 3025  199 The d-and f-Block Elements Report Error

Solution:

Zinc does not have unpaired electrons in ground state as well as in its common oxidation state. Enthalpy of atomisation depends upon the number of unpaired electrons. Greater the number of unpaired electrons, stronger is the interatomic metallic bonding and higher is the enthalpy of atomisation.