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Isaac Newton
Idea: all things are made up of indivisible particles which he called “atomos”, from which the word atom derives from and that only void and atoms exist. -
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John Dalton
Idea: Atomic theory. His theory states that, 1.All matter originates from atoms and they are indivisible and imperishable.
2.Atoms of a specific elements all share the same mass and properties.
3.Compounds are made from two or more different atoms.
4.A rearrangement of the atoms creates a chemical reaction. -
G.J. Stoney
Idea: electricity was made of negative particles which he called “electrons” -
J.J. Thomson
Thomson found the charge to mass ratio of an electron as 1.759 x 10 8 coulombs/gram. -
Max Planck
Planck’s radiation law: explains radiation emitted by blackbody using quanta. -
Nagaoka
Created a “Saturnian” model with rings of electrons orbiting a positive particle. -
R.A. Millikan
Experiment: Oil drop which determined the size of the electron. -
Ernest Rutherford
Through a experiment, Rutherford found the nucleus to be small, dense and positively charged and that the electrons are outside the nucleus. -
H.G.J. Moseley
Moseley’s idea was that the atomic number of an element is the number of protons the element has. -
Niels Bohr
Suggested a model of the atom that had shells of electrons which orbited the atom. -
James Chadwick
Proved the existence of neutrons, particles with no electrical charge