The first ionization enthalpies of $N$ and $O$ are respectively....... $eV$.

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The first ionization enthalpy of $O$ is lower than that of $N$ and $F$.
Reason $R$: The loss of an electron from $O$ leads to a stable half-filled $p$ orbital.
In light of the above statements, choose the most appropriate answer from the options given below:

Mercury is the only metal which is liquid at $0 \, ^{\circ}C$. This is due to its

Identify the element having lowest first ionization enthalpy.

Which of the following electronic configurations has the highest ionization enthalpy?

The first ionization enthalpy of $Al$ is lower than that of $Mg$ because .......................