Periodic Properties and Ion Formation

Dr. Walt Volland revised July 12, 2013 all rights reserved



Ionization happens when an electron is stripped off of a particle. If enough energy is available all the electrons on an atom can be removed. The first electron removed requires the least energy. Progressively more energy is needed as the positive change on the ionized particle goes up and as the electron being removed comes from an orbital cloer to the nucleus of the atom.

The ionization energy is the amount of energy needed to strip an electron off of an atom, ion, or molecule.

The illustration shows that the metals like lithium, Li, and cesium, Cs, have relatively low ionization energies. This means it takes relatively small amounts of energy to remove electrons from these atoms. These atoms have large diameters. The outer electrons are relatively far from the nucleus. Metals tend to lose electrons and form positive ions.

The nonmetals like neon, Ne, fluorine, F, and oxygen, O, have relatively high ionization energies. This indicates that the nonmetals have strong attractions for their valence electrons. The nonmetals hold on to their electrons. In fact nonmetals gain electrons to form negative ions. Click here to see more discussion of ionization energies for various elements.

Which atom fluorine or calcium is more likely to lose an outer electron? click here for answer