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 :-

Observe the following statements.
Statement $(A)$: In general,the ionisation potential value decreases on moving down in the group.
Statement $(B)$: The $1$st ionisation potential of sodium is greater than that of potassium.
Correct answer is:

The second ionisation potential of an element $M$ is the energy required to

Assertion : Element has a tendency to lose the electron$(s)$ to attain the stable configuration.
Reason : Ionization enthalpy is the energy released to remove an electron from an isolated gaseous atom in its ground state.

Which of the following orders regarding ionization energy is correct?

Triad-$I$ $[N^{3-}, O^{2-}, Na^{+}]$
Triad-$II$ $[N^{+}, C^{+}, O^{+}]$
Choose the species of lowest $IP$ from triad-$I$ and highest $IP$ from triad-$II$ respectively.