Editing Atomic number (section)

== Notation ==
[[File:Atomic number depiction.svg|thumb|300px|An explanation of the superscripts and subscripts seen in [[AZE notation]]. Atomic number is the number of protons, and therefore also the total positive charge, in the atomic nucleus.|alt=This is a diagram that explains AZE notation. On the left is a model of an atom, with a nucleus in the middle consisting of two circular protons marked with a "+" symbol tightly placed next to two blue neutrons. A ring surrounds the nucleus, containing two circular electrons that are smaller than the neutrons and the electrons. A description for protons says in a neutral atom they are the same as the number of electrons. On the right is the AZE notation of Helium, with the chemical symbol He with a superscript and subscript to the left of the symbol. The superscript, 4, is the atomic / mass number, the sum of the protons and neutrons. The subscript, 2, is the number of protons.]]The atomic number is used in [[AZE notation]], (with ''A'' as the [[mass number]], ''Z'' the atomic number, and E for [[Chemical element|element]]) to denote an [[isotope]]. When a [[chemical symbol]] is used, e.g. "C" for carbon, standard notation uses a [[superscript]] at the upper left of the chemical symbol for the mass number and indicates the atomic number with a [[subscript]] at the lower left (e.g. {{nuclide|He|3}}, {{nuclide|He|4}}, {{nuclide|C|12}}, {{nuclide|C|14}}, {{nuclide|U|235}}, and {{nuclide|U|239}}).  Because the atomic number is given by the element symbol, it is common to state only the mass number in the superscript and leave out the atomic number subscript (e.g. {{SimpleNuclide|He|3}}, {{SimpleNuclide|He|4}}, {{SimpleNuclide|C|12}}, {{SimpleNuclide|C|14}}, {{SimpleNuclide|U|235}}, and {{SimpleNuclide|U|239}}).

The common pronunciation of the AZE notation is different from how it is written: {{nuclide|He|4}} is commonly pronounced as helium-four instead of four-two-helium, and {{nuclide|U|235}} as uranium two-thirty-five (American English) or uranium-two-three-five (British) instead of 235-92-uranium.
Various notations appear in older sources were used, such as
Ne(22) in 1934,<ref>Scientific Papers of the Institute of Physical and Chemical Research. (1934). Japan: The Institute</ref>{{rp|226}} Ne<sup>22</sup> for neon-22 (1935)<ref>Archives neerlandaises des sciences exactes et naturelles: Ser. 4A. (1935). Netherlands: North Holland.</ref> or  Pb<sub>210</sub> for lead-210 (1933)<ref>[https://books.google.com/books?id=HD7OAAAAMAAJ&q=isotope Scientific Papers.] (1933). Japan: (n.p.).</ref>{{rp|7}}