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460
Democritus
DemocritusDemocritus was a Greek Philosopher and is credited with naming particles atoms. He was the father of the atomic theory and belived that each substance had atoms of unique shapes and sizes. Democritus also believed that the atoms were infinite in number and always moving. -
Period: 460 to
History of Atomic Theory
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John Dalton
John DaltonJohn Dalton changed the idea of the atomic theory based on his experiments. He believed that all matter is made of atoms and that they are indivisibe and indestructable. Dalton also claimed that all atoms of a given element are identical in mass and properties. He proposed the Law of Partial Pressures and said that atoms resembled spheres. -
J.J. Thomson
J.J. ThomsonJ.J. Thomson was the first scientist to discover that atoms consisted of smaller subatomic particles. He found that there was a positive and negative section of atoms. Thomson proposed a "plum pudding" model of an atom and won the Nobel Prize in Physics. -
Max Planck
Max PlanckMax Planck was a German Physicist that is credited with formulating an equation which described the blackbody spectrum. Planck received the Nobel Prize in physics in 1918 for his quantum theory after it had been successfully applied to the discoveries of others. -
Ernest Rutherford
Ernest RutherfordErnest Rutherford was a student of Thomson's and found that Thomson's model was incorrect. Rutherford used very thin gold foil to determine that positive charge was located in the center, or nucleus, of the atom and that most of the atom is empty space. His model is reffered to as a planetary and he won a Nobel Prize in Chemistry in 1908. -
Francis Aston
Francis AstonFrancis Aston was a British physicist that that won a Nobel Prize in Chemistry for his discovery of a vast number of isotopes and using a mass spectrometer. The mass spectrometer is a device that separates atoms of different masses and measures those masses with great accuracy. Aston also developed the "whole-number rule" which states that isotopes have masses that are proportional of the mass of hydrogen. -
Neils Bohr
Neils BohrNeils Bohr refined Rutherford's model. Bohr proposed the idea of electrons and how they orbit the nucleus on fixed amount of energies. He said that electrons with low energy would orbit close to the nucleus while electrons with high energy would orbit farther away. His model was based on mathematics and experimentation and he won the Nobel Prize in Physics. -
Erwin Schrodinger
Erwin SchrodingerErwin Schrödinger was a noted physicist who came up with a brilliant wave equation for electron movements. He was awarded the 1933 Nobel Prize in Physics for his work. -
James Chadwick
James ChadwickJames Chadwick was a student of Rutherford and made many advances on his previous. Chadwick proved Rutherfords idea that a neutral particle existed. According to Chadwick, this particle, known as the neutron, had around the same mass as a proton and took residence in the nucleus. -
Louis de Brogile
Louis de BrogileLouis de Brogile made expansions on other scientists experiments. He devoted most of his time to studying wave mechanics and developed the equation "mc² = hv." -
Werner Heisenberg
Werner HeisenbergWerner Heisenberg is know forhis theory of quantum mechanics which he published in 1925. His new theory was applied to other studies and numerous notable experiments. Heisenberg won Nobel Prize for Physics for 1932. -
Paul Dirac
Paul DiracPaul Dirac is known for his famous wave equation, which introduced special relativity into Schrödinger's equation. Dirac's equation was remarkable considering that the two theories are opposite of each other.
