$$ \text { The first to fifth ionization energies (IE) of two p-block elements } X \text { and } Y \text { are given below. } $$

$$ \begin{array}{|c|c|c|c|c|c|} \hline & \mathrm{IE}_1(\mathrm{eV}) & \mathrm{IE}_2(\mathrm{eV}) & \mathrm{IE}_3(\mathrm{eV}) & \mathrm{IE}_4(\mathrm{eV}) & \mathrm{IE}_5(\mathrm{eV}) \\ \hline \mathbf{X} & 6.0 & 18.8 & 28.4 & 120.0 & 153.7 \\ \hline \mathbf{Y} & 8.2 & 16.3 & 33.5 & 45.1 & 166.7 \\ \hline \end{array} $$

$$ \text { The number of valence electrons in } X \text { and } Y \text { respectively are } $$

Which among the following is NOT correct regarding the first ionization potential $\left(\mathrm{IP}_1\right)$ of period $I I I$ elements $M g, A l, S i, P$ and $S$ ?