The correct values of ionization enthalpies (in $kJ \ mol^{-1}$) of $Si, P, Cl$ and $S$ respectively are

Discuss and compare the trend in ionisation enthalpy of the elements of group-$1$ with those of group-$17$ elements.

The ionization energy of nitrogen is more than that of oxygen because

The incorrect statement among the following is:

The ionization potentials of $Li$ and $K$ are $5.4 \ eV$ and $4.3 \ eV$ respectively. The ionization potential of $Na$ will be .............. $eV$.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ The energy required to form $Mg^{2+}$ from $Mg$ is much higher than that required to produce $Mg^{+}$.
Reason $R:$ $Mg^{2+}$ is a small ion and carries more charge than $Mg^{+}$.
In the light of the above statements,choose the correct answer from the options given below: