Which of the following represents the correct order of increasing first ionization enthalpy for $Ca, Ba, S, Se$ and $Ar$?

The successive ionization energy values for an element $X$ are given below:
$(i)$ $1^{st}$ ionization energy $= 410 \ kJ \ mol^{-1}$
$(ii)$ $2^{nd}$ ionization energy $= 820 \ kJ \ mol^{-1}$
$(iii)$ $3^{rd}$ ionization energy $= 1100 \ kJ \ mol^{-1}$
$(iv)$ $4^{th}$ ionization energy $= 1500 \ kJ \ mol^{-1}$
$(v)$ $5^{th}$ ionization energy $= 3200 \ kJ \ mol^{-1}$
Find the number of valence electrons in the atom $X$.

The first four ionization energy values of an element are $191$,$578$,$872$ and $5962 \ kcal$. The number of valence electrons in the element is

Which among the following species has the highest ionisation potential?

Assertion $(A)$: Boron has a smaller first ionisation enthalpy than beryllium.
Reason $(R)$: The penetration of a $2s$-electron to the nucleus is more than the $2p$-electron; hence,the $2p$-electron is more shielded by the inner core of electrons than $2s$-electrons.

Which of the following elements has the maximum first ionization potential?