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1778 BCE
antoine lavoisier
Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. -
1754 BCE
Joseph Louis Proust
Joseph Louis Proust (26 September 1754 – 5 July 1826) was a French chemist. He was best known for his discovery of the law of constant composition in 1794, stating that chemical compounds always combine in constant proportions. -
1627 BCE
Robert Boyle
Robert Boyle. Known for his law of gases, Boyle was a 17th-century pioneer of modern chemistry. Every general-chemistry student learns of Robert Boyle (1627–1691) as the person who discovered that the volume of a gas decreases with increasing pressure and vice versa—the famous Boyle's law. -
1546 BCE
George Bauer
German, development of systematic metallurgy, extraction of metals from ores -
470 BCE
Democritus
Democritus was a Greek philosopher who lived between 470-380 B.C. He developed the concept of the 'atom', Greek for 'indivisible'. Democritus believed that everything in the universe was made up of atoms, which were microscopic and indestructible. -
384
Aristotle
The Greek philosopher Aristotle (384-322 B.C.) made significant and lasting contributions to nearly every aspect of human knowledge, from logic to biology to ethics and aesthetics. -
John Dalton
Although two centuries old, Dalton's atomic theory remains valid in modern chemical thought. 1) All matter is made of atoms. Atoms are indivisible and indestructible. 3) Compounds are formed by a combination of two or more different kinds of atoms. -
Joseph Louis Lussac
He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen, for two laws related to gases, and for his work on alcohol-water mixtures, it led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries. -
Amadeo Avogadro
In 1811 Avogadro put forward a hypothesis that was neglected by his contemporaries for years. Eventually proven correct, this hypothesis became known as Avogadro’s law, a fundamental law of gases. -
J.J Thomson
discovered the electron by experimenting with a crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas. -
Henri Becquerel
French physicist who discovered radioactivity through his investigations of uranium and other substances. In 1899 & 1900, the deflection of beta particles, which are a constituent of the radiation in both electric and magnetic fields. From the charge to mass value thus obtained, he showed that the beta particle was the same as Joseph John Thomson’s recently identified electron. -
Ernest Rutherford
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure. -
Niels Bohr
proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. -
Robert Millikan
Robert Millikan measured the charge on an electron In these experiments, the atomizer from a perfume bottle was used to spray water or oil droplets into a sample chamber. Some of these droplets fell through a pinhole between two plates of an electric field, where they could be observed through a microscope. -
Max Planck
Originator of the quantum theory of energy for which he was awarded the Nobel Prize in 1918. His work contributed significantly to the understanding of atomic and subatomic processes. -
Louis de Broglie
Broglie developed his revolutionary theory of electron waves, which he had published earlier in scientific journals. -
Erwin Schrodinger
He used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model of the atom. -
Werner Heisenberg
Best known for his uncertainty principle and theory of quantum mechanics, that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory.
