The correct option for the first ionisation enthalpy (in $kJ \ mol^{-1}$) of $Li$,$Na$,$K$ and $Cs$ respectively is

The first ionisation energies (in $kJ \ mol^{-1}$) of four consecutive elements of the second period are given in the options. The first ionisation energy of nitrogen is

Consider the following ionization enthalpies of two elements $A$ and $B$.

Element	Ionization enthalpy $(kJ \ mol^{-1})$ $(1^{st}, 2^{nd}, 3^{rd})$
$A$	$899, 1757, 14847$
$B$	$737, 1450, 7731$

Which of the following statements is correct?

Consider the following changes:
$M_{(s)} \to M_{(g)}$ ........$(1)$
$M_{(s)} \to M^{2+}_{(g)} + 2e^-$ .......$(2)$
$M_{(g)} \to M^{+}_{(g)} + e^-$ .........$(3)$
$M^{+}_{(g)} \to M^{2+}_{(g)} + e^-$ .........$(4)$
$M_{(g)} \to M^{2+}_{(g)} + 2e^-$ ..........$(5)$
The second ionization energy of $M$ could be calculated from the energy values associated with:

Which one of the following orders is correct for the first ionisation energies of the elements?

In a group of elements,as the atomic number increases,which of the following is $NOT$ observed?