A materials chemist compares the energy required for selected successive ionizations of three neighboring period- elements. The gaseous ions are formed by successive removal of valence electrons from isolated atoms.

Ionization energy	Process
\(\operatorname{IE}_1(\text{P})\)	\(\text{P(g)} \rightarrow \text{P}^{+}\text{(g)}+e^-\)
\(\operatorname{IE}_2(\text{S})\)	\(\text{S}^{+}\text{(g)} \rightarrow \text{S}^{2+}\text{(g)}+e^-\)
\(\operatorname{IE}_3(\text{Cl})\)	\(\text{Cl}^{2+}\text{(g)} \rightarrow \text{Cl}^{3+}\text{(g)}+e^-\)

Which of the following correctly ranks the ionization energies from greatest to least and provides the best justification?