A counter ion is an ion, the presence of which allows the formation of an overall neutrally charged species. For example, in the (neutral) species NaCl the sodium ion is countered by the chloride ion and vice versa. In most situations in chemistry, an ion has a counter ion, exceptions being in ion beams, mass spectrometry and situations where electrons counter the charge of the ion (e.g. the Na/NH₃ system, and plasmas). “Multivalent” redirects here. ... Look up charge in Wiktionary, the free dictionary. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Standard atomic weight 22. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. ... An ion beam is a stream of charged particles, which has many uses in electronics manufacturing (principally ion implantation) and other industries. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... Cavities and channels in Electride An electride is an ionic compound in which an electron is the anion. ... A plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. ...