-Democritus(460-370 BCE) believed that there are spaces between atoms, and believed that atoms are indestructible
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-Aristotle(384-322 BCE)also believed that all things were made of matter, and believed that they can be broken down into 4 types: Air, Water, Earth and Fire
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-Isaac Newton(1642-1717)believed that there were small solid masses that were in motion
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-John Dalton(1766-1844) believed in 4 different theories:
1.All matter were made up of invisible particles called atoms
2.Atoms of different elements had different properties
3.All the atoms of an element are identical in size and mass
4.Atoms of different elements can combine to create different substances
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-Eugen Goldenstein(1850-1930) helped discovered the proton. He discovered that they were positively charge and moved in different directions
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-J.J.Thomson(1865-1940) discovered the electron
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-Max Planck(1858-1947) discovered the Quantum Theory
-Hantaro Nagoka(1865-1950) created his own atom model, known as the Plum Pudding Model
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-Robert Andrews Millikan (1868 - 1953)
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-Ernest Rutherford (1871 – 1937) believed that atoms have their protons in their very small nucleus. The model of the atom came to be because of his discovery.
-Albert Einstein (1879 - 1955) explained the Brownian movement as well as the photoelectric effect using quantum mechanics
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-Neils Bohr (1885 - 1962) came up with the Bohr model. Which depicts the atom as a small, positively charged nucleus surrounded by electrons. These electrons travel in circular orbits around the nucleus, similar in structure to the solar system.
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-Erwin Schrödinger (1887 - 1961) used a sophisticated mathematical equation too calculate of finding the electron.
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-James Chadwick (1891 - 1974) discovered that there were neutrally charged particles as well as positively charged particles
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-Satyendra Nath Bose (1894 - 1974) discovered a sub atomic particle called "boson"
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-Enrico Fermi (1901 - 1954) developed the nuclear reactor and also worked on the first ever atomic bomb.
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-Peter Higgs (1929- Present) was the first one who thought about the god particle. (The Higgs boson, or “God particle,” is believed to be the particle which gives mass to matter)