Which of the following groups of elements loses an electron most easily?

Which of the following configurations represents atoms of the elements having the highest second ionization energy?

"On moving left to right,ionization energy increases due to increasing $Z_{eff}$." In which of the following pairs is the above statement $NOT$ $CORRECT$?

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 electronic configuration of an element with the largest difference between the $1^{st}$ and $2^{nd}$ ionisation energies is

The correct order of second ionisation potentials $(IP)$ of $Ca$,$Ba$ and $K$ is