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100
Democritus and Leucippos c.400 BC
Believed that matter could be broken into small indivisible particles and named them atoms. (The timeline doesn't allow BC dates) -
Period: Jan 1, 1493 to Dec 31, 1541
Paracelsus (Philippus Theophrastus Bombastus von Hohenheim)
At some point in his life, he worked on the medicinal application of minerals. -
Period: Jan 1, 1494 to Dec 31, 1555
Georg Baur
Sometime in his life, Georg Baur developed specific metallurgy, which is the extraction of metals from their ores. -
Period: to
Robert Boyle
He published a book, The Skeptical Chemist, in 1661 about the carefully measured relationship between between the pressure and volume of air. He also said that elements could not be broken into simpler substances. -
Period: to
Joseph Priestley
He used combustion to discover oxygen gas and also discovered carbon dioxide to be used in seltzer. -
Period: to
Antoine Lavoisier
At some point in his life, he discovered that mass is neither created nor destroyed (Law of Conservation of Mass). He published the first modern textbook in 1789. -
Period: to
Joseph Proust
At some point in his life, he discovered that a given compound always contains exactly the same proportion of elements by mass (Law of Definite Porportions). -
Period: to
John Dalton
He discovered the Law of Multiple Proportions. His atomic theory was published in 1808. He also made the first periodic table of atomic mases. -
Period: to
Amadeo Avogadro
He proposed that at the same temperature and pressure, equal volumes of different gases contain the same number of particles. -
Period: to
Joseph Gay-Lussac
He worked on the system of giving compounds chemical formulas. -
Period: to
Jons Jakob Berzelius
He discovered 4 elements, including selenium. He came up with a simple way of symbolizing th eelements and the chemical formulas. -
Period: to
J.J. Thomson
He used the cathode ray tube experiment to discover the electron. He determined the charge to mass ratio of the electron. He theorized the atom with the plum pudding model. -
Period: to
Robert Millikan
Using th eoil drop experiment with x-rays, he determined the magnitude and mass of the electron. -
Henri Becquerel
He discovered radioactivity accidentally by leaving uranium with photographic paper. -
Ernest Rutherford
Using th egold foil experiment, he discovered that the plum pudding model was not accurate because he discovered that the atom has a positively charged nucleus.