How many Cl atoms can you ionize in the process of Cl → Cl + e^– by the energy liberated for the process Cl + e^– →Cl^– for one Avogadro number of atoms? Given IP = 13 eV and EA = 3.60 eV.

Ionization potential is the energy required to remove an electron from the outermost shell of an atom.

$\mathrm{Cl}⟶{\mathrm{Cl}}^{+}+{\mathrm{e}}^{-} ; \mathrm{E}=13.0 \mathrm{eV}$

Electron affinity is the property of an atom to attract an electron.

$\mathrm{Cl}+{\mathrm{e}}^{-} ⟶\mathrm{Cl} ;\mathrm{E}=-3.6 \mathrm{eV}$

Moles of Cl atoms that can be ionized=$\frac{3.6}{13}=0.277\mathrm{moles}$

No. of atoms= 0.277×6.022×10²³=1.667×10²³ atoms.