Main Page | See live article | Alphabetical index When an atom, radical, or ion has an equal number of electrons or has the same number of electrons when compared to the atoms of another element, the two species are called isoelectronic. Examples: Sodium is isoelectronic to neon when it loses one electron When Na+=[He]2s22p6 it is isoelectronic to Ne=[He]2s22p6 Chlorine is isoelectronic to argon when it gains an electron When Cl-=[Ne]3s23p6 it is isoelectronic to Ar=[Ne]3s23p6 This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.