The first ionisation potential is maximum for

Which of the following electronic configurations will have the least $I.P.$ value?

Which of the following electronic configurations will have the highest tendency to form a univalent gaseous cation?

The energy required to remove an electron of a gaseous atom from its ground state is called

The electronic configuration which is associated with the highest first ionisation enthalpy is:

If the successive ionisation energies of an element $A$ are $165$,$190$,$550$ and $595 \ kcal$,respectively,then the ground state electronic configuration of element $A$ is