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460
Democritus
Developed the theory of the atomic nature- everything is composed of atoms and that they are invisible. -
Isaac Newton
He proposed the idea of a mechanical universe with solid masses in motion. Dalton used and understood the law of motion and used it to discover that atoms were an infinite vacuum. -
John Dalton
The idea of "atomic theory" with spherical atoms based on properties of mass that were measureable. He recorded a logbook of entries with the first use of symbols to represent the modern elemenets. Today we can easily determine the element and its symbol based on Dalton's work. -
George Stoney
He made the theory that electricity was composed of tiny negative particles he called "electrons". Stoney's discovery of the atom helped understand the atom in many different ways. Before this, the atom was thought to be an indistinguishable unit of an element. With the discovery of an electron, scientists have a better understanding of the atom alone and that it isn't the smallest unit in the world. -
JJ Thompson
Studied "canal rays" and discovered that they were associated with the proton H+. He also determined the charge to mass ratio of an electron using a CRT. With Thompson's discovery, we know that electron clouds exist and how many electrons there are in each electron cloud. -
Max Planck
Explained glowing hot water using the idea of discrete units of energy. He developed the Quantum theory. The discovery changed the nature of physics by proving the idea and nature of radiation and energy wrong. -
Albert Einstein
Einstein's 1905 paper explaining Brownian motion proved that such motion was evidence that atoms existed. They had already been theorized before, but Einstein proved it. -
Robert Millikan
Experimented with an oil drop to determine the charge and the mass of an electron. Ever since the electric field was discovered, the charge on the oil drops could be used to determine when the drops were at stable. The charge from a single electron can also be measured. -
Ernest Rutherford
Established that the nucleus was a very small and dense, positively charged particle. He also assumed that electrons were located outside the nucleus. His model supported Nagaoka's model. -
Neils Bohr
Developed an explanation for atomic structure that followed the periodic table. More knowledge of the atom's structure and the radiation that is emitted from his work. -
Erwin Schrodinger
Schrodinger discovered the equation that can be used to determine the probability of an electron's location at a given position in relation to the nucleus. Also he proposed the interesting idea of: Why not go all the way with particle waves and try to form a model of the atom on that basis? His theory worked similarly to harmonic theory except that the vibrations traveled in circles.
