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427 BCE
Plato
Plato introduced the atomic theory in which ideal geometric forms serve as atoms, according to which atoms broke down mathematically into triangles, such as the form elements had the following shape. -
427 BCE
Solar System Model
This model was made by Plato -
400 BCE
Democritus
Democritus held a theory that everything is composed of atoms, which are physically, but not geometrically, invisible, that between atoms, there lies empty space. -
384 BCE
Aristotle
Aristotle thought that all materials on earth were not made of atoms, but of the four elements, earth, fire, air, and water. He believed all substances were made up of small amounts of these four elements of matter. -
Robert Boyle
His major contribution to the atomic theory was that he helped develop a definition of an element. He also helped people change the way they think about science. -
Lavoisier
Lavoisier found the total mass of products and reactants in a chemical reaction that is always the same. -
John Dalton
His most important contribute to science was that matter is composed of atoms of differing weights and combine in simple ratios by weight. -
Solid Sphere of Billiard Ball Model
John Dalton discovered the Solid Sphere of Billiard Ball Model. -
Dmitiri Mendeleev
Mendeleev found that when all the known chemical elements were arranged in order increasing by atomic weight. -
The Curies
Marie and her husband Pierre Curie discovered Polonium and Radium and was awarded a Nobel Prize in physics and chemistry for her discovery of the two elements. -
J.J. Thomoson
Thomoson proposed a model of the atom as a sphere of positive matter with electrons positioned based on electrostatic forces. -
Plum Pudding Model
J.J. Thomson made this model. -
Albert Einstein
Einstein mathematically proved the existence of atoms and helped revolutionize al the sciences through the use of statistics and probability. -
Robert Millikon
Millikon succeeded in precisely determining the magnitude of the electrons charge -
Ernest Rutherford
Rutherford postulated the nuclear structure of the atom, discovered alpha and beta rays, and proposed the laws of Radioactive decay. -
Neils Bohr
Neils proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in a certain well defined quantities. -
Henry G.J. Mosely
Mosely demonstrated that the major properties of an element are determined by the atomic number, not by the atomic weight -
Electron Cloud Model
Made by Werner and Erwin -
Werner Heisenberg
Werner developed a key piece of the quantum theory, the uncertainty principal, with profound implications.
