-
330
Four elements.
Aristotle proposes the four element theory: earth, air, fire & water -
360
Plato coins term ‘elements’ (stoicheia)
Plato coins term ‘elements’ (stoicheia) -
440
Atoms were made.
Democritus and Leucippus propose the idea of the atom, an indivisible particle that all matter is made of. -
Sir Francis Bacon published a book.
Sir Francis Bacon published "The Proficience and Advancement of Learning" which contained a description of what would later be known as the scientific method. -
Robert Boyle published a book.
Robert Boyle published "The Sceptical Chymist" which was a treatise on the distinction between chemistry and alchemy. It also contained some of the earliest ideas of atoms, molecules, and chemical reaction marking the beginning of the history of modern chemistry -
Period: to
Timespan of when elements were created.
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Joseph Black isolated carbon dioxide.
Joseph Black isolated carbon dioxide, which he called "fixed air". -
Oxygen was isolated.
Carl Wilhelm Scheele and Joseph Priestly independently isolated oxygen -
Hydrogen was discovered.
Henry Cavendish discovered hydrogen as a colorless, odourless gas that burns and can form an explosive mixture with air -
Antoine Lavoisier wrote the first list of elements.
Antoine Lavoisier wrote the first extensive list of elements containing 33 elements & distinguished between metals and non-metals -
"Dalton's Law" was proposed.
John Dalton proposed "Dalton's Law" describing the relationship between the components in a mixture of gases. -
Johann Dobereiner developed groups.
Johann Dobereiner developed groups of 3 elements with similar properties -
Jakob Berzelius developed a table
Jakob Berzelius developed a table of atomic weights & introduced letters to symbolize elements -
The known elements were arranged.
John Newlands arranged the known elements in order of atomic weights & observed similarities between some elements -
Lothar Meyer developed a version.
Lothar Meyer develops an early version of the periodic table, with 28 elements organized by valence -
Dimitri Mendeleev produced a table.
Dimitri Mendeleev produced a table based on atomic weights but arranged 'periodically' with elements with similar properties under each other. His Periodic Table included the 66 known elements organized by atomic weights. -
Noble Gases were discovered.
William Ramsay discovered the Noble Gases. -
Radium and Polonium were isolated.
Marie and Pierre Curie isolated radium and polonium from pitchblende. -
Ernest Rutherford discovered a source.
Ernest Rutherford discovered the source of radioactivity as decaying atoms -
The "Periodic Law" was modified.
Henry Moseley determined the atomic number of each of the elements and modified the 'Periodic Law'. -
Glenn Seaborg synthesised transuranic elements.
Glenn Seaborg synthesised transuranic elements (the elements after uranium in the periodic table) -
Neptunium was identified.
Edwin McMillan and Philip H. Abelson identify neptunium, the lightest and first synthesized transuranium element, found in the products of uranium fission.