Editing Ionization (section)

==Ionization energy of atoms==
[[File:First Ionization Energy blocks.svg|thumb|right|512px|Ionization energies of neutral elements (predicted beyond 104)]]
The trend in the [[ionization energy]] of atoms is often used to demonstrate the periodic behavior of atoms with respect to the atomic number, as summarized by ordering atoms in [[Mendeleev's table]]. This is a valuable tool for establishing and understanding the ordering of electrons in [[atomic orbitals]] without going into the details of wave functions or the ionization process. An example is presented in the figure to the right. The periodic abrupt decrease in ionization potential after rare gas atoms, for instance, indicates the emergence of a new shell in [[alkali metals]]. In addition, the local maximums in the ionization energy plot, moving from left to right in a row, are indicative of s, p, d, and f sub-shells.