Question

In the $3$d series from Sc$(z=21)$ to Zn$(z=30)$, enthalpy of atomisation of Zn is the lowest.

Answer 1

The Zn having the atomic number 30 and is an element of 3d series. The enthalpy of atomization depends on the extensive metallic bonding which in turn depends on the number of unpaired electrons. Due to the absence of these unpaired electrons in Zn. The interatomic bonding is weak in Zn and hence the enthalpy of atomization of Zn is the lowest.