From the following elements,which of them has the highest second ionisation potential?

Which of the following elements will have the lowest first ionisation energy?

Which is the correct order of second ionization potential of $C, N, O$ and $F$ in the following?

The electronic configuration which is associated with the highest first ionisation enthalpy is:

The ionization potential $(IP)$ values for an element are given below. Identify the element:

$(IP)_1$	$7.1 \ eV$
$(IP)_2$	$10.3 \ eV$
$(IP)_3$	$36.2 \ eV$
$(IP)_4$	$39.1 \ eV$

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 $X$.