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Democritus
Democritus and his mentor, Leucippus came up with the atomic theory. He hypothesized that atoms cannot be destroyed, differ in size, shape and temperature, are always moving, and are invisible -
John Dalton
came up with a spherical model,determines that atoms of a given element are identical in size, mass, and chemical properties -
J.J Thomson
AKA plum pudding model,he discovered that atoms are made of positive cores and negatively charged particles within it and it can be divided -
Ernst Rutherford
known for his gold foil experiment, determined the nucleus from J.J Thomson's pudding -
Niels Bohr
discovered that electrons orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
James Chadwick
proved the existence of neutrons, fundamental for nuclear weapons. -
Aristotle
He believes that all materials on Earth were made up of four elements; earth,air, fire, and water in small amounts. Most people believed in his idea, causing Democritus' idea to be overlooked for about 2,000 years.
