The first ionization potential of $Na, Mg, Al$ and $Si$ are in the order:

Given below are two statements $:$
Statement $(I) :$ The first ionisation enthalpy of group $14$ elements is higher than the corresponding elements of group $13.$
Statement $(II) :$ Melting points and boiling points of group $13$ elements are in general much higher than those of the corresponding elements of group $14.$ In the light of the above statements,choose the most appropriate answer from the options given below $:$

The graph shows the variation of Ionization Potential $(I.P.)$ with Atomic Number $(At. No.)$ for elements $A$ to $E$. If these elements belong to the same group in the periodic table,identify the group.

Assertion $(A)$: First ionisation enthalpy of oxygen is less than that of nitrogen.
Reason $(R)$: Atoms with half-filled or completely filled orbitals are less stable.
The correct option among the following is:

The element having the highest first ionization enthalpy is

Which of the following transitions involves the maximum amount of energy?