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460
Democritus
Democritus first suggested the existence of an atom. -
Period: 460 to
Scientists
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Antoine Lavoisier & law of conservation of mass
States that an object's mass will stay constant over time. -
John Dalton + Dalton atomic theory
All matter is made of atoms. Atoms are indivisible and indestructible.All atoms of a given element are identical in mass and properties Compounds are formed by a combination of two or more different kinds of atoms.A chemical reaction is a rearrangement of atoms. - Daltons atomic theory -
Dmitri Mendeleev
Dmirti first rearranged 63 elements on the Periodic table, fixing their position. -
Ernest Rutherford + Gold foil experiment
Established that the plum pudding is not exactly true when alpha particles are put through a piece of gold foil. -
J.J Thomson and plum pudding model and Cathode ray experiment
J.J Thomson's plum pudding model stated that negative charges were surrounded in a positively charged sort of "puddle".
His Cathode ray experiment discovered the electron. -
Henry Moseley
Corrected the positioning of elements on the periodic table. -
Niels bohr & Bohr Planetary model
Established that electrons orbit the nucleus of an atom similar to planets orbiting the sun. -
Quantum mechanical model by Schrodinger
Stated that electron cannot be found in one spot for any amount of time and involves quantum numbers -
Schrodinger 's Electron cloud Model
The electron cloud model stated that electrons are in a cloud and cannot be pinpointed to one spot, but where they could be.
