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427 BCE
Plato
He believed there were more than 2 elements -
Period: 427 BCE to
Atomic theory
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400 BCE
Democritus
Central figure in the devolpment of atomic theory of the universe. -
400 BCE
The alchemists
They heavily studieed fermentation, distilation, sublimation, calcination -
330 BCE
Solar system model
A model that illustrates the positions and mosions of our solar system -
Robert Boyle
Boyles Theory: States that a gas's pressure and volume are proportional -
Antone Lavoisier
Father of modern chemistery -
Billiard ball model
Daltons way of modeling an atom -
John Dalton
introduced atomic theory -
Amedeo Avogadro
Believed equal volume of gas contain equal number of molecules. Elementry gases are composed of 2 atoms. -
Dmitri Mendeleev
Discovered periodic law and arranged the elements in the periodic table -
JJ Thompson
Discovered the electron -
Pierre and Marie Curie
Discovered 2 radioactive elements: Polonium, and Radium -
Ernest Rutherford
discovered the 2 types of radiation: non-ionizing radiation and ionizing radiation. -
Plum pudding model
Depicts electrons in a cloud around the dense nucleus -
Robert Millikan
Discovered the electronic charge of an electron using the oil-drop experiment -
Neils Bohr
Proposed a model of an atom in which the electron was able to occupy only certain orbits around the nucleus -
Henry G.J. Mosely
Moselys law: State that the square root of the frequency of the emitted x-ray is proportional to the atomic number. -
Albert Einstein
Discovery of the Phebelectric Effect. -
Erwin Schrödinger
Schrödinger equation: Describes the evolution of the wave function -
Electron cloud model
Discovered by Erwin Schrödinger. An electron cloud represents the area around an atom's nucleus where electrons are most likely to be found. -
James Chadwich
Discovery of the Neutron