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Dalton hypothesized that the law of conservation of mass and the law of definite proportions could be explained using the idea of atoms.
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Came up with elements
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the Greek philosopher Democritus introduced the idea of the atom as the basic building block matter.
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Aristotle believed that elements were the building blocks of chemical substances, only potentially present in these substance
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He thought of the possibility of atoms existing, but his work was greatly diagreed by the church.
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Antoine Lavoisier was a key figure in the field of chemistry in the late 18th century. He consolidated the research of many of his contemporaries into a coherent theory of elements, which he defined as indivisible particles which we have found no means of separating.
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His first discussion of these issues dates to 1803, and he presented his atomic theory in the multivolume New System of Chemical Philosophy.
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Because Dalton thought atoms were the smallest particles of matter, he envisioned them as solid, hard spheres, like billiard (pool) balls, so he used wooden balls to model them.
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Dmitri Mendeleev devised the periodic classification of the chemical elements, in which the elements were arranged in order of increasing atomic weight.
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The photoelectric effect proves that light has particle-like activity. The photoelectric effect happens when photons are shone on metal and electrons are ejected from the surface of that metal
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The timeline of quantum mechanics is a list of key events in the history of quantum mechanics, quantum field theories and quantum chemistry.
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The Curies shared the 1903 Nobel Prize in physics with Antoine Henri Becquerel.
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The plum pudding model is one of several historical scientific models of the atom. First proposed by J. J. Thomson in 1904 -
Einstein also in 1905 mathematically proved the existence of atoms, and thus helped revolutionize all the sciences through the use of statistics and probability.
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Concluded a small, dense, positively charge nucleus as the result of the alpha particles scattering gold foil experiment
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During the 1890s the theory that electricity was conveyed by a miniscule unit, the electron, gained acceptance. In 1910 Robert Millikan succeeded in precisely determining the magnitude of the electron's charge.
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In July of 1913, Danish physicist Niels Bohr published the first of a series of three papers introducing this model of the atom, which became known simply as the Bohr atom
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The "solar system" model describes an atom as a central massive positive entity (the nucleus/sun) and, orbiting around it, the negative entities (the electrons/planets). -
Physicist Henry Moseley discovered the atomic number of each element using x-rays, which led to more accurate organization of the periodic table.
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By 1920, physicists knew that most of the mass of the atom was located in a nucleus at its center, and that this central core contained protons.
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Schrödinger used mathematical equations to describe the likelihood of finding an electron in a certain position.
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we cannot know exactly where an electron is at any given time, but the electrons are more likely to be in specific areas. -
In 1904, Thomson proposed a model of the atom as a sphere of positive matter with electrons positioned based on electrostatic forces. So, he not only discovered the electron but determined it was a fundamental part of an atom.
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Heisenberg was a main contributor to the German atomic program during World War II, in direct competition with the Manhattan Project.
