Question

Which of the following transition elements will exhibit the least enthalpy of atomisation?

• A. $Zn$
• B. $Sc$
• C. $Co$
• D. $Mn$

Answer 1

The correct option is A $Zn$

Outer electronic configuration of $Zn=3d^{10}4s^2$.
Outer electronic configuration of $Sc=3d^{1}4s^2$.
Outer electronic configuration of $Co=3d^{7}4s^2$.
Outer electronic configuration of $Mn=3d^{5}4s^2$.

In general, the greater the number of unpaired electrons, the stronger is the resultant bonding and hence, higher is the enthalpy of atomisation. In the $3d$ series, from $Sc$ to $Zn$, $Zn$ has no unpaired electrons. Hence, it exhibits weak interactions and thus possesses the least enthalpy of atomisation.