The weights here are taken from
http://www.iupac.org/publications/pac/2003/7508/7508x1107.html
and have been rounded to four significant figures in all cases.
In the case of elements that have no isotopes stable enough for
reasonable measurement, numbers have been updated from Zumdahl,
"Chemistry", Fifth edition and are presented (as before) in parentheses.
2) Cesium is now C{a}esium
3) A number of new elements have been added at the end of the periodic
table.
Although the traditional spelling in commonwealth countries is
"Sulphur", the official IUPAC name of the element is "Sulfur", and
even the Royal Society of Chemistry now spells it "Sulfur".
