Which of the following elements has the highest second ionisation potential?

The first ionization enthalpy $(\Delta_{i} H)$ values of the third period elements,$Na, Mg$ and $Si$ are respectively $496, 737$ and $786 \, kJ \, mol^{-1}$. Predict whether the first $\Delta_{i} H$ value for $Al$ will be more close to $575$ or $760 \, kJ \, mol^{-1}$? Justify your answer.

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

The ionisation energy of nitrogen is more than oxygen because of $:-$

Given below are two statements:
Statement $I$: The first ionization energy of $Pb$ is greater than that of $Sn$.
Statement $II$: The first ionization energy of $Ge$ is greater than that of $Si$.
In the light of the above statements,choose the correct 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.