Source:http://linkedlifedata.com/resource/umls/id/C0020275
MSH: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.,CSP: first chemical element in the periodic table; atomic symbol H, atomic number 1; it exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas; hydrogen ions are protons.