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

Which one of the following elements has the highest ionisation energy?

The electronic configurations 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 $C$?

Find the incorrect comparison of second ionisation energy.

Consider the elements $Mg$,$Al$,$S$,$P$ and $Si$. The correct increasing order of their first ionization enthalpy is:

Which of the following presents the correct order of second ionization enthalpies of $C$,$N$,$O$ and $F$?