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

The decreasing order of the ionisation potential in the following elements is

Which one of the following statements is incorrect in relation to ionisation enthalpy?

Which of the following represents the correct order of ionization enthalpy?
$(i) Be^{+} > Be$ $(ii) Be > Be^{+}$ $(iii) C > Be$ $(iv) B > Be$

If first ionization enthalpies of element $X$ and $Y$ are $419 \ kJ \ mol^{-1}$ and $590 \ kJ \ mol^{-1}$,respectively and second ionization enthalpies of $X$ and $Y$ are $3069 \ kJ \ mol^{-1}$ and $1145 \ kJ \ mol^{-1}$,respectively. Then the correct statement is :-

Discuss the trend of the first ionisation enthalpy in the same period and explain why it occurs.