The correct order of first ionization enthalpy values of the following elements is:
$A. O$,$B. N$,$C. Be$,$D. F$,$E. B$
Choose the correct answer from the options given below:

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 $X$.

Amongst the elements with the following electronic configurations,which one of them may have the highest ionisation energy?

Consider the following ionisation reactions:

$A_{(g)} \to A^{+}_{(g)} + e^-, \ A_1$	$B_{(g)} \to B^{+}_{(g)} + e^-, \ B_1$
$B^{+}_{(g)} \to B^{2+}_{(g)} + e^-, \ B_2$	$C_{(g)} \to C^{+}_{(g)} + e^-, \ C_1$
$C^{+}_{(g)} \to C^{2+}_{(g)} + e^-, \ C_2$	$C^{2+}_{(g)} \to C^{3+}_{(g)} + e^-, \ C_3$

If the monovalent positive ion of $A$,divalent positive ion of $B$,and trivalent positive ion of $C$ have zero electrons,then which of the following is the incorrect order of the corresponding $I.E.$?

The first ionization energy of magnesium is smaller as compared to that of elements $X$ and $Y$,but higher than that of $Z$. The elements $X$,$Y$ and $Z$,respectively,are :

If the successive ionisation energies of an element $A$ are $165$,$190$,$550$ and $595 \ kcal$,respectively,then the ground state electronic configuration of element $A$ is