Generally,the first ionisation energy increases along a period. But there are some exceptions. The one which is not an exception is

If $X$ and $Y$ are the second ionisation potentials of alkali and alkaline earth metals of the same period,then:

Which of the following elements has the highest first ionization enthalpy?

Given below are two statements:
Statement $(I)$: The first ionisation enthalpy of the elements $Na$, $Mg$, $Cl$ and $Ar$ follows the order $Na > Mg > Cl > Ar$.
Statement $(II)$: Among $Ca$, $Al$, $Fe$ and $B$, the third ionisation enthalpy is very high for $Ca$.

First and second ionization enthalpies of lithium are $520 \text{ kJ mol}^{-1}$ and $7297 \text{ kJ mol}^{-1}$ respectively. Energy required to convert $3.5 \text{ mg}$ lithium $(g)$ into $Li^{2+}(g)$ [$Li(g) \rightarrow Li^{2+}(g)$] is . . . . . . $\text{kJ}$. (nearest integer) [Molar mass of $Li = 7 \text{ g mol}^{-1}$]

Which of the following has the least ionization potential?