Developments In Atomic Theory

Timeline created by killercupcake in Science and Technology

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Event Date:	Event Title:	Event Description:
01/01/1704	Isaac Newton	Proposed a mechanical universe with small solid masses in motion. One of the earliest in modern science to suggest atomic nature of matter.
01/01/1803	John Dalton	Idea of atomic theory, and that atoms were indivisible. His idea of atomic theory was more detailed than previous ones, and stated that the atoms of elements were different because of the different masses.
01/01/1894	G.J. Stoney	Proposed idea of electrons. Led to further study of electrons and electrical charge.
01/01/1897	J.J. Thomson	Discovery of electrons, and suggesting a different view for the atom. Changed our views of the atom. His idea contributed to the current idea of how the atom is structured.
01/01/1900	Max Planck	Quantum theory. More knowledge about the nature of matter.
01/01/1903	Nagaoka	Model of the atom resembling Saturn. His predictions were that the nucleus was very large, and that the electrons revolved around the nucleus.
01/01/1909	R.A. Millikan	Oil drop experiment to determine the charge and mass of an electron. Discovered the charge of an electron.
01/01/1911	E. Rutherford	Gold foil experiment – suggested that the atom was consisted of a dense core (nucleus). Provided new ideas about the atom, about how the nucleus was positively charged etc.
01/01/1914	H.G.J. Moseley	Determined charges on the nuclei of most atoms using x-ray tubes. Concluded that the atomic number of an element is equal to the number of protons in the nucleus. This contributed to the periodic table.
01/01/1922	Niels Bohr	Developed an explanation of atomic structure. Now called the Bohr model, the model of the atom shows the orbital shells of electrons.
01/01/1932	James Chadwick	Discovered the neutron. Helped to further our understanding of the atom.