The elements of Group $13$ with highest and lowest first ionisation enthalpies are respectively$:$

The first ionization energy (in $kJ / mol$) of $Na, Mg, Al$ and $Si$ respectively,are

As compared to potassium,sodium has

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 ionisation potential will be maximum for

The first ionization energy of alkaline earth metals is higher than that of alkali metals. This is due to...