An atom with high electronegativity has

The successive ionisation enthalpies of an element $X$ in $(kJ \ mol^{-1})$ are $1012$,$1907$,$2955$,$4955$,$6275$ and $21,260$ respectively. The element $X$ is:

The correct order of second $I.E.$ of $C$,$N$,$O$,and $F$ is:

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 value of ionization energy of noble gases is ......... .

Correct increasing order of first ionisation potential is