Get unlimited access to ad-free articles and exclusive content. Standard atomic weights, those numbers emblazoned under the elements on the periodic table, were once thought of as unchanging constants ...

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 ...

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 ...

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 ...

Ytterbium is a bit lighter than previously thought: Its standard atomic weight is now 173.045, down from 173.054, as approved by the International Union of Pure & Applied Chemistry (IUPAC) in August.

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 ...

More than 40 years after scientists first detonated a nuclear device in the Trinity test, composer and conductor James Yannatos assembled over 350 musicians for an unusual memorial. In April 1986, 90 ...