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The Alchemists started testing Aristotle's theory of atomic shortly after Aristotle's death. Then, in 500 B.C., they discovered a substance that would transmute more common metals into silver and gold.
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Plato came up with the idea of Elements in 428 B.C.
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in 400 B.C. Democritus created a theory that posited that matter is made up of small indestructible units called atoms.
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in 1640, Robert Boyle discussed the possibility of atoms existing, he proposed that the elements are composed of "corpuscles" of various sizes and types that can be able to organize themselves into groups that represent different chemical substances. -
In 1777, Antone Lavoisier was a French chemist who proved the conservation of matter and explained the mysteries of fire. In 1778, he named and recognized oxygen. -
John Dalton was an English chemist and teacher who used experimental evidence to form the Atomic Theory of Matter. In 1803 A.D. John Dalton proposed that compounds were atoms from different elements combined together and consisted of atoms that were identical and also had the same mass. He also came up with the Billiard Ball Model in 1803.
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John Dalton, in 1803, put forth the theory of the solid sphere or as it was also called, "Billiard Ball" model -
Created the Avogadro's Hypothesis, which reasoned that simple gasses were not formed of solitary atoms but were instead compound molecules of 2 or more atoms in 1811
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Dmitri Mendeleev created the periodic table in 1869. -
in 1897, JJ Thompson determined the charge to mass ratio of electrons. he also created the Plum Pudding Model in 1900.
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in 1898, Pierre and Marie Curie identified and studied radioactive elements
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JJ Thompson came up with the "Plum Pudding" theory thinking an atom had many positive and negative charges, in 1900
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Albert Einstein proposed the quantum of light in which he stated that light is like a particle and also has a wave nature that is giving a dual nature. He also started the equivalence of energy and mass through the theory of special relativity.
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In 1908, Robert Millikan discovered the charge of an electron with his oil drop experiment -
Ernest Rutherford, in 1909, concluded a small, dense positively charged nucleus as a result of the alpha particles in a scattering gold foil experiment. Created the Solar System Model as well in 1900
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in 1911, Ernest Rutherford came up with the theory of the solar system and said an atom looked somewhat like it. He also discovered the nucleus of an atom.
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In 1913, Neils Bohr proposed an atomic structure theory that stated the outer orbit of an atom could hold more electrons than the inner orbit. -
In 1914, Mosely discovered that the number of protons in an element is its atomic number.
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one electron cloud model example was proposed by Erwin Schrodinger and Werner Heisenburg in 1926, though there were other models of the Electron Cloud Model, such as the one by Neils Bohr and the one by Ernest Rutherford. -
In 1926, Werner Heisenburg, along with Erwin Schrodinger, created the Electron Cloud model
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in 1926, Erwin Schrodinger, along with Werner Heisenburg, created the Electron Cloud model.
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in 1932, James Chadwich discovered that atoms consisted not only of protons and electrons but also neutrons.
