the threat of CFCs to the ozone layer in the stratosphere (1974) was explained

by Mario J. Molina Frank Sherwood Rowland in a paper for the journal Nature



the Miller-Urey experiment (1953)


the Turing mechanism (1952)



the electron microscope (1933)



Bohr's model of the atom was superseded by the probability cloud model of Erwin Schrödinger and Werner Heisenberg



Heisenberg's Uncertainty Principle (1927)


Lewis Acid-Base Theory (1923)


the existence of the neutron (1920) was suggested by William Draper Harkins.

Evidence for its existence was not obtained until 1932


Hermann Staudinger explained that polymeres (1920) are

long-chain molecules held together by ordinary valency bonds


the Czochralski process (1916)


Gilbert N. Lewis proposed the idea of covalent bonds (1916) and introduced the electron-dot notation



the Sommerfeld model of the atom (1916)



isotopes (1913) were discovered by J. J. Thomson


Moseley's law (1913)



the Bohr model of the atom (1913)



the Rutherford model (1911)


the Geiger-Marsden experiment (1909)


the Henderson-Hasselbalch equation (1908)


the mole (1902)



the electron (1897) was discovered as a a subatomic particle by Joseph John Thomson. As a unit
of charge in electrochemistry the electron was posited by G. Johnstone Stoney already in 1874


the hydrogenation process (1897) was discovered by Paul Sabatier


the idea that changes in the levels of carbon dioxide in the atmosphere (1896) could substantially

alter the surface temperature through the greenhouse effect was first formulated by Svante Arrhenius


Svante Arrhenius' work on the conductivities of electrolytes (1884)


Karol Olszewski, Zygmunt Wróblewski and Karol Sitarski (1883) were the first to

liquefy oxygen, nitrogen and carbon dioxide from the atmosphere in a stable state


the Erlenmeyer Rule (1880)


Josiah Willard Gibbs' On the Equilibrium of Heterogeneous Substances (1876-1878) laid the foundations of physical chemistry


van der Waals' forces (1869)



the periodic table of elements (1869)


Dynamite (1866) was invented by Alfred Nobel


Avogadro's number (1865)



the carbon ring structure of benzene (1865) was proposed by Friedrich August Kekulé von Stradonitz


pasteurization (1862)


the Erlenmeyer flask (1861)


Stanislao Cannizzaro's Sunto di un corso di Filosofia chimica (1858)


the first aniline dye, mauveine (1856) was discovered accidentally by William Perkin


Johann Loschmidt (1856) determined the size of the molecules in air


Robert Bunsen started using a burner developed by his technician (1855) this burner quickly becomes

known as the Bunsen burner, although credit for its invention should really go to Michael Faraday


nitrocellulose (gun cotton) (1845) was acidentally discovered by Christian Schönbein




the first enzyme (1833) diastase was discovered by Anselme Payen


Urea (1828) was the first organic compound to be artificially synthesized from inorganic starting materials


hydrogen peroxide (1818) was discovered by Louis-Jacques Thénard


Jöns Jakob Berzelius developed the system of chemical notation (1813) in which

each element is represented by the initial letter or pairs of letters from their names


Amedeo Avogadro (1810) distinguished between atoms and molecules


Gay-Lussac's law (1809)



John Dalton's New System of Chemical Philosophy (1808)


Chemicals were classified as either organic or inorganic (1807) by the Swedish chemist Jöns Jakob Berzelius


the fact that acids and bases neutralise in equal proportions (1791) was discovered by Jeremias Richter



Joseph Priestley (1772) showed that growing plants can restore air

that has been made 'lifeless' by animals breathing it or fire burning in it


Joseph Black's experiments on magnesia, quicklime (1755) and other

alkaline substances was the first quantitative chemical research


carbon dioxide (1754) was discovered by Joseph Black


Daniel Gabriel Fahrenheit invented the first mercury thermometer (1714)


Boyle's law (1662)


the phlogiston theory (1660)


Andreas Libavius' Alchemia (1597)



Agricola's De re metallica (1556)


Paracelsus (1520) pioneered the use of chemicals and minerals in medicine


Hermeticism (1460)


Albertus Magnus isolated arsenic (1250)


Al-Razi's books on medicine and chemistry (925)



Jabir Ibn Hayyan (750) turned alchemy into a science



the Islamic Golden Age (700-1400)



the Emerald Tablets (300)


the Corpus Hermeticum