Standard atomic weight precise value is acceptable, CIAAW has published a single-number conventional atomic weight that can be used for example in trade. For hydrogen, . The twelve elements are: hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine and thallium. By using the abridged value, and the conventional value for the twelve interval values, a short IUPAC-defined value (5 digits plus uncertainty) can be given for all stable elements. In many situations, and in periodic tables, this may be sufficiently detailed. Standard atomic weight The standard atomic weight ("A", a relative atomic mass) is the atomic weight ("A") of a
Isotopes of flerovium Isotopes of flerovium Flerovium (Fl) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was Fl in 1999 (or possibly 1998). Flerovium has seven known isotopes, and possibly 2 nuclear isomers. The longest-lived isotope is Fl with a half-life of 1.9 seconds, but the unconfirmed Fl may have a longer half-life of 19 seconds. The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with an atomic number of 114. "This section deals