The correct trend in the first ionization enthalpies of the elements in the $3^{rd}$ period of periodic table is:

In which of the following electronic configurations of an element is there a very large difference between the second and third ionization energy?

The correct order of first ionization enthalpy for the given four elements is:

The correct increasing order of ionisation enthalpy of $He, Li^{+}, Be^{2+}$ is

Which of the following pairs has a higher ionization enthalpy?
$(i)$ $Ne$ or $Ar$ $(ii)$ $Cl$ or $F$ $(iii)$ $F$ or $O$ $(iv)$ $N$ or $O$
$(v)$ $Na$ or $K$ $(vi)$ $Cl$ or $S$ $(vii)$ $Kr$ or $Xe$ $(viii)$ $P$ or $S$

For $Mg$,the values of $\Delta_iH_1$ and $\Delta_iH_2$ are $178 \, kcal \, mol^{-1}$ and $348 \, kcal \, mol^{-1}$ respectively. The enthalpy change for the reaction $Mg \to Mg^{2+} + 2e^-$ is ............. $kcal \, mol^{-1}$.