isoelectronic sequence

Isoelectronic sequence

A term used in spectroscopy to designate the set of spectra produced by different chemical elements ionized in such a way that their atoms or ions contain the same number of electrons. The sequence in the table is an example. Since the neutral atoms of these elements each contain Z electrons, removal of one electron from scandium, two from titanium, and so forth, yields a series of ions all of which have 20 electrons. Isoelectronic sequences are useful in predicting unknown spectra of ions belonging to a sequence in which other spectra are known. See Atomic structure and spectra

isoelectronic sequence