2. Quantities defining atoms and elements

2.1 Name and symbol

Most of these symbols have long since been adopted, except for recently-discovered unstable elements, for which IUPAC proposes a systematic nomenclature. This nomenclature is backed up by a 3-letter symbolism (one capital and two small letters). Each digit (from 0 to 9) of the atomic number units is assigned a letter (0 = N for Nil, 1 = U for Un...). Element 103 is thus assigned the symbol Unt and the name unniltrium, while the last known element (Z = 118) is given the name ununoctium, and its symbol is Uuo. In addition to the 3-letter symbol, elements from Z = 104 to 112 have been given names and thus chemical symbols, following a 2002 IUPAC recommendation to name new elements after "a mythological concept, a place, a country, a property or a scientist". These...