Which element has the maximum first ionization potential?

The electronic configuration of elements $A, B$ and $C$ are $[He] 2s^1, [Ne] 3s^1$ and $[Ar] 4s^1$ respectively. Which one of the following orders is correct for the first ionization potentials (in $kJ \ mol^{-1}$) of $A, B$ and $C$?

The first ionization enthalpies of four consecutive elements present in the second period of the periodic table are $8.3, 11.3, 14.5$ and $13.6 \ eV,$ respectively. Which one of the following is the first ionization enthalpy of nitrogen?

In the long form of the periodic table,the elements having the lowest ionisation potentials are present in:

Which of the following processes is non-spontaneous?

Which of the following is a favourable factor for cation formation?