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460
Democritus
Speculates about the world being made up of atoms. -
Issac Newton
Proposes that the world is made up of small bodies in motion. -
John Dalton
Discovers that all particles are made up of atoms and are drawn togethers to form matter through the attraction of cohesion and affinity. Dalton also published the first six atomic weights to be given to elements. He explained why elements grouped together in whole ratios as well. -
John Newlands
Published his law of octaves. -
Johann Loschmidt
Measures molecules in the air, first time molecules or atoms given any dimension of how big or small they are. -
Dmitri Mendeleev
Presents and publishes his periodic table in the order of their chemical properties which formed a pattern. -
Goldstein
Working with cathode rays and anode rays helped lead to the discoveries of the electron and the proton. -
J.J. Thompson
Discovers the electron while stuyding cathode rays, and helps develop the plum pudding model. -
Rutherford
Develops his theory of the atom which included a positive nucleus orbited by electrons. He discovered this through his experiments with gold foil and bombarding it with electrons. -
Neils Bohr
Stated that electrons are in defined quantized orbits and could only move between the different orbits by absorbing energy quanta. -
Frederick Soddy
Discovered there were multipleatoms for each position on the periodic table. This lead to the term isotopes for different elements. -
Max Planck
Discoveries about quanta help explain the different energy levels within the atom and how electrons move. Also lead to quantum mechanics. -
Louis de Brogile
Proposes that electrons and all particles have some form of wave like behavior. -
Erwin Schrodinger
Discovered that the movement of electrons could be modeled in an equation. Electrons move more like waves than particles. The equation is know called Schrodinger's equation. -
James Chadwick
Discovers the neutron through ionization testing.
