1852 Edward Frankland introduces the idea of valency—the number of bonds an atom can form with other atoms.
1858 Archibald Couper suggests that carbon atoms can link directly to one another, forming chains.
1858 Italian chemist Stanislao Cannizzaro explains the difference between atoms and molecules, and publishes atomic and molecular weights.
1869 Dmitri Mendeleev lays out the periodic table.
1931 Linus Pauling elucidates the structure of the chemical bond in general, and that of the benzene molecule in particular, using the ideas of quantum mechanics.
The early years of the 19th century saw huge developments in ...