atomic number (proton number), \(Z\)

https://doi.org/10.1351/goldbook.A00499
The number of protons in the atomic @N04256@.
Sources:
Green Book, 2nd ed., p. 20 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 962 [Terms] [Paper]
Red Book, 3rd ed., p. 35 [Terms] [Book]