The relative atomic masses of elements are proportional measures. For example, the Ar for helium is 4.0, and the A r for carbon is 12.0. This means that carbon atoms have three times the mass of ...

In 1923, the year C&EN was born, Gilbert N. Lewis of the University of California, Berkeley, published a book titled “Valence and the Structure of Atoms and Molecules.” In the text, Lewis laid out the ...