Long before anyone wrote a chemical equation, people smelted copper, fired pottery, brewed beer and dyed cloth. They knew how to change matter. Chemistry is the story of finding out why it changes.
This article follows that story in six steps: the ancient crafts, the philosophers’ theories of matter, alchemy, the scientific revolution, the discovery of atoms and elements, and the twentieth-century look inside the atom.
Fire, metals and the first chemists
The first chemical technology was fire. With it came cooking, pottery and, around 5000 BCE, the smelting of copper from its ores. Mixing copper with tin gave bronze (from about 3300 BCE), harder than either metal alone. Iron working spread after about 1200 BCE.
Ancient Egypt and Mesopotamia produced glass, cosmetics, perfumes and dyes. These artisans followed recipes passed down for generations. They had no theory of matter, but they were running chemical reactions every day.
The philosophers: elements and atoms
Greek thinkers asked what everything is made of. Empedocles (5th century BCE) proposed four roots — earth, water, air and fire — and Aristotle built them into a system that lasted almost two thousand years.
Around 400 BCE, Leucippus and Democritus offered a different answer: matter is made of tiny, indivisible particles they called atomos, “uncuttable”. It was a brilliant guess, but with no way to test it, the atom stayed a philosophical idea until the 1800s.
Alchemy: the laboratory before chemistry
Alchemy appeared in Hellenistic Egypt, in Alexandria, and was later developed by scholars of the Islamic world and of medieval Europe. Alchemists sought to transform base metals into gold and to find an elixir of long life. Those goals failed, but their methods did not.
- Writers in the Arabic tradition, under the name of Jābir ibn Ḥayyān, described distillation, crystallization and the classification of substances.
- Al-Rāzī (Rhazes, 9th–10th century) sorted materials into minerals, plants and animal products and described laboratory equipment in detail.
- In the 16th century, Paracelsus turned alchemy toward medicine, using minerals as remedies — the start of what was called iatrochemistry.
Distillation flasks, furnaces, crucibles and the habit of keeping laboratory notes came from alchemy. So did strong acids and concentrated alcohol.
The scientific revolution: measuring matter
In 1661 Robert Boyle published The Sceptical Chymist, attacking the four elements and arguing that claims about matter must be tested by experiment. In 1662 he published the relationship between the pressure and volume of a gas now known as Boyle’s law.
The most popular theory of the 18th century was phlogiston, proposed by Johann Becher and Georg Stahl. Burnable things were thought to contain phlogiston, which escaped when they burned. It explained a lot, but not one stubborn fact: metals get heavier when they are heated in air.
The chemical revolution
In the middle of the 18th century, chemists learned to collect and study gases. Joseph Black identified “fixed air” (carbon dioxide) in the 1750s, Henry Cavendish isolated hydrogen in 1766, and Carl Wilhelm Scheele and Joseph Priestley both prepared oxygen in the early 1770s.
Antoine Lavoisier put the pieces together. By weighing everything before and after reactions in closed vessels, he showed that burning is combination with oxygen and that mass is conserved. His Elementary Treatise of Chemistry (1789) defined an element as a substance that cannot be broken down further and listed 33 of them.
Lavoisier’s story, from his experiments to his execution in 1794, has its own article.
Atoms, formulas and the periodic table
In 1803–1808 John Dalton revived the atom with something the Greeks lacked: numbers. Each element has its own kind of atom with a characteristic mass, and compounds form from fixed whole-number ratios of atoms. Amedeo Avogadro (1811) separated atoms from molecules, and Jöns Jacob Berzelius introduced the letter symbols we still use — H, O, Fe.
In 1828 Friedrich Wöhler made urea, a substance from living things, out of inorganic starting materials, helping open the field of organic chemistry. In 1865 August Kekulé proposed the ring structure of benzene.
In 1869 Dmitri Mendeleev arranged the 63 known elements by atomic weight and chemical behaviour, and left gaps for elements nobody had found yet. When gallium (1875), scandium (1879) and germanium (1886) turned up with the properties he had predicted, the periodic table was accepted. Read more in What is the Periodic Table.
Inside the atom
At the end of the 19th century, the “indivisible” atom came apart. Henri Becquerel discovered radioactivity in uranium in 1896; J. J. Thomson discovered the electron in 1897; Marie and Pierre Curie found polonium and radium in 1898. Ernest Rutherford’s gold foil experiment revealed the nucleus in 1911, and Niels Bohr placed electrons in energy levels in 1913.
Quantum mechanics, developed in the 1920s, finally explained why atoms bond. In 1939 Linus Pauling’s The Nature of the Chemical Bond made quantum ideas the everyday language of chemists. See the models side by side in the atomic models viewer.
Chemistry in the modern world
Twentieth-century chemistry changed daily life. The Haber–Bosch process (1909–1913) made fertilizer from the nitrogen in the air. Bakelite (1907) and nylon (1935) began the age of plastics. Chemists built the medicines, semiconductors and batteries of the modern world — and also faced their costs, from pollution to industrial disasters such as Bhopal.
Today the field includes green chemistry, which designs processes that avoid hazardous substances and waste. In 2016 the names of the last four elements of the seventh period were approved, completing the table up to oganesson, element 118.
Timeline
- ~5000 BCE — Copper smelting. The first metals are extracted from ores with fire.
- ~400 BCE — Atomos. Leucippus and Democritus propose that matter is made of indivisible particles.
- 1661 — The Sceptical Chymist. Robert Boyle calls for experiment over tradition.
- 1774 — Oxygen. Priestley publishes his “dephlogisticated air”; Scheele had prepared it independently.
- 1789 — Lavoisier’s Treatise. Conservation of mass and a modern list of elements.
- 1808 — Dalton’s atoms. Atomic theory with measurable atomic masses.
- 1869 — Periodic table. Mendeleev predicts elements that had not yet been discovered.
- 1898 — Polonium and radium. Marie and Pierre Curie study radioactivity.
- 1911 — The nucleus. Rutherford shows that the atom’s mass is concentrated in a tiny core.
- 2016 — Element 118 named. Oganesson completes the seventh period.
Frequently asked questions
Who is called the father of modern chemistry?
Antoine Lavoisier is usually called the father of modern chemistry. In the 1770s and 1780s he explained combustion as a reaction with oxygen, showed that mass is conserved in reactions and helped create the modern names of chemical substances.
Was alchemy a science?
Alchemy mixed practical laboratory work with mystical and philosophical goals, such as turning base metals into gold. It was not a science in the modern sense, but alchemists developed distillation, crystallization and much of the equipment that chemistry still uses.
When did chemistry become a science?
Historians usually place the change between Robert Boyle’s The Sceptical Chymist (1661) and Lavoisier’s Elementary Treatise of Chemistry (1789), when careful measurement and testable theories replaced older ideas.
What were the four elements?
Many ancient Greek thinkers, following Empedocles and Aristotle, held that everything was made of earth, water, air and fire. The idea lasted for about two thousand years until experiments showed that air and water are themselves made of simpler substances.
References and further reading
- Brock, W. H. — The Norton History of Chemistry. W. W. Norton, 1993.
- Principe, L. M. — The Secrets of Alchemy. University of Chicago Press, 2013.
- Science History Institute — historical biographies of Boyle, Lavoisier, Dalton and Mendeleev.
- IUPAC — Naming of the new elements 113, 115, 117 and 118 (2016).