Standard atomic weights, those numbers emblazoned under the elements on the periodic table, were once thought of as unchanging constants of nature. But researchers have tweaked the atomic weights of ...

One hundred years ago the Harvard University chemist Theodore William Richards was awarded the 1914 Nobel Prize in Chemistry for his accurate determination of the atomic weights of many elements. This ...

Thank you for bringing to my attention the recent International Union of Pure & Applied Chemistry report “Atomic weights of the elements 2009” (C&EN, Dec. 20 ...

Nineteen elements on the periodic table — including gold, cadmium, arsenic and aluminum — are getting their atomic weights adjusted. The International Union of Pure and Applied Chemistry (IUPAC) ...

Mass spectrometry—a technology that is constantly being made more accurate and reliable—is used every two years to revise the standard atomic weights of select elements. This year, the International ...

A magnificent period piece from mid-19th-century Russia has just received a bit of a renovation. Five elements at the heart of the periodic table will never look the same again, following an update to ...

A magnificent period piece from mid-19th-century Russia has just received a bit of a renovation. Five elements at the heart of the periodic table will never look the same again, following an update to ...

1863: British chemist John Newlands organizes the known elements, listing them in a table determined by atomic weight, according to what he provisionally calls his "law of octaves." It is not an ...