Which from following series of elements is CORRECTLY arranged according to their decreasing order of…
Which from following series of elements is CORRECTLY arranged according to their decreasing order of ionization enthalpy $\left(\mathrm{IE}_1\right)$ ?
$\mathrm{Zn}>\mathrm{Fe}>\mathrm{Cr}>\mathrm{Sc}$
$\mathrm{Cr}>\mathrm{Fe}>\mathrm{Zn}>\mathrm{Sc}$
$\mathrm{Sc}>\mathrm{Fe}>\mathrm{Cr}>\mathrm{Zn}$
$\mathrm{Cr}>\mathrm{Zn}>\mathrm{Sc}>\mathrm{Fe}$
Solution
The ionization enthalpy $\left(\mathrm{IE}_1\right)$ of the elements of the $3 \mathrm{~d}$ transition series increases gradually from left to right with some irregularities. Therefore, the decreasing order of ionization enthalpy $\left(\mathrm{IE}_1\right)$ is: $\mathrm{Zn}>\mathrm{Fe}>\mathrm{Cr}>\mathrm{Sc}$