$A \to A^{+} + e, E_{1}$ and $A^{+} \to A^{2+} + e, E_{2}$. The energy required to pull out the two electrons are $E_{1}$ and $E_{2}$ respectively. The correct relationship between the two energies is:

Which of the following elements has the lowest $IE_1$ value?

Ionization energy of gaseous $Na$ atoms is $495.5 \ kJ \ mol^{-1}$. The lowest possible frequency of light that ionizes a sodium atom is $(h = 6.626 \times 10^{-34} \ J \ s, N_A = 6.022 \times 10^{23} \ mol^{-1})$.

Sodium generally does not show an oxidation state of $+2$,because of its

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:

$B$ 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: