Editing Ionization energy (section)

===Electron binding energy===
[[File:Electron binding energy vs Z.jpg|thumb|500px|Binding energies of specific atomic orbitals as a function of the atomic number. Because of the increasing number of protons, electrons occupying the same orbital are more tightly bound in heavier elements.]]

Electron [[binding energy]] is a generic term for the minimum energy needed to remove an electron from a particular electron shell for an atom or ion, due to these negatively charged electrons being held in place by the electrostatic pull of the positively charged nucleus.<ref>{{cite web |url=https://radiopaedia.org/articles/electron-binding-energy#:~:text=The%20electron%20binding%20energy%20is,1.6%20x%2010-19%20J. |title=Electron binding energy |last1=Murphy |first1=Andrew |last2=Wong |first2=Monica |date=2019 |website=radiopaedia.org |publisher=Radiopaedia |access-date=December 7, 2020 |quote=The electron binding energy is the minimum energy that is required to remove an electron from an atom}}</ref> For example, the electron binding energy for removing a 3p<sub>3/2</sub> electron from the chloride ion is the minimum amount of energy required to remove an electron from the chlorine atom when it has a charge of −1. In this particular example, the electron binding energy has the same magnitude as the [[electron affinity]] for the neutral chlorine atom. In another example, the electron binding energy refers to the minimum amount of energy required to remove an electron from the dicarboxylate dianion <sup>−</sup>O<sub>2</sub>C(CH<sub>2</sub>)<sub>8</sub>CO{{su|b=2|p=−}}.

The graph to the right shows the binding energy for electrons in different shells in neutral atoms. The ionization energy is the lowest binding energy for a particular atom (although these are not all shown in the graph).