Chemical element of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin "natrium". The same applies to "W" (wolfram) for tungsten, "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "K" (kalium) for potassium, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and
Standard atomic weight "atomic" either, as it does not correspond to the property of any individual atom. The same argument could be made against "relative atomic mass" used in this sense. IUPAC publishes one formal value for each stable element, called the "standard atomic weight". Any updates are published biannually (in uneven years). The last change was published in 2015, setting a new value for ytterbium In 2017, no changes were published. The value published can have and uncertainty be an "interval" like for neon: , or can be an interval, like for boron: [10.806, 10.821]. Next to these 84 values, IUPAC also