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:

Explain why there is a phenomenal decrease in ionisation enthalpy from carbon to silicon?

The first ionization energy of alkaline earth metals is higher than that of alkali metals. This is due to...

The atomic numbers of $V, Cr, Mn$ and $Fe$ are $23, 24, 25$ and $26$ respectively. Which of these elements will have the highest second ionization enthalpy?

The $3^{rd}$ ionisation energy amongst $Li$,$Be$,$B$ and $C$ is lowest for

$B$ has a smaller first ionization enthalpy than $Be$. Consider the following statements:
$(I)$ It is easier to remove a $2p$ electron than a $2s$ electron.
$(II)$ The $2p$ electron of $B$ is more shielded from the nucleus by the inner core of electrons than the $2s$ electrons of $Be$.
$(III)$ The $2s$ electron has more penetration power than the $2p$ electron.
$(IV)$ The atomic radius of $B$ is more than $Be$.
(Atomic number: $B=5, Be=4$)
The correct statements are: