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400 BCE
Democritus
He theorized that all material bodies were made up of "atoms"
He was living around the time Aristotle was alive and he actually disagreed with his theories.
https://www.britannica.com/biography/Democritus -
400 BCE
Plato
He thought atoms were derived from the 4 basic Greek elements but he theorized a 5th one, ether. He was also Aristotle's teacher.
https://www.britannica.com/biography/Plato -
500
The Alchemists
They tried to manipulate matter and change one element to another
Their study also included philosophy. It started in as old as Ancient Egypt but the exact date is unknown
https://www.britannica.com/topic/alchemy -
Robert Boyle
He claimed everything was made up of a single universal matter. He published books detailing matter's composition in 1661
He also published Boyle's law
https://www.britannica.com/biography/Robert-Boyle -
Antoine Lavoiser
Made an experiment which led to the law of conservation of mass, which stated atoms could not be made or destroyed. He also coined the term "oxygen" for the gas we know today. https://www.britannica.com/biography/Antoine-Lavoisier#ref218476 -
John Dalton
He made a theory that atoms who were the same repelled each other and that atoms who weren't the same didn't.
He also is best known for Dalton's law
https://www.britannica.com/biography/John-Dalton -
Billiard Ball Model
Proposed by John Dalton
https://www.cram.com/essay/The-Evolution-Of-Atoms-The-Billiard-Ball/FCUK5JMEMG -
Amedeo Avogadro
He stated his hypothesis of gases which claimed equal volumes of all gases at the same pressure and temperature have the same amount of molecules. He also rarely left his hometown of Turin, Italy.
https://www.britannica.com/biography/Amedeo-Avogadro -
Dmitri Mendeleev
Devised the Periodic table system where the elements were arranged in order of atomic weight. He was a professor of chemistry at the university of St. Petersburg. https://www.britannica.com/biography/Dmitri-Mendeleev -
JJ Thomson
Discovered the electro. He proposed a model consisting of positive and negatively charged atoms. https://www.britannica.com/biography/J-J-Thomson -
Pierre and Marie Curie
Conducted pioneering research on radioactivity. They discovered Radium and Polonium. https://www.britannica.com/biography/Pierre-Curie
https://www.britannica.com/biography/Marie-Curie -
Plum pudding model
Proposed by William Thomson, strongly supported by J.J. Thompson
https://www.britannica.com/science/Thomson-atomic-model -
Albert Einstein
He mathematically proved the existence of atoms, he developed his most famous formula, E=mc^2 which just means energy and mass are the same just in different forms. He also won the Nobel Prize in Physics 1921
https://www.britannica.com/biography/Albert-Einstein -
Robert Millikan
He discovered the charge carried by an electron (Negative). He also won the Nobel Prize in Physic 1923. He also discovered the Photoelectric effect.
https://www.britannica.com/biography/Robert-Millikan -
Ernest Rutherford
He discovered that the atom is mostly empty space with everything packed into a small nucleus. He won the Nobel Prize in 1908.
https://www.britannica.com/biography/Ernest-Rutherford -
Neils Bohr
Proposed the model of an atom which the electrons were limited to an orbit. He also won a Nobel Prize in Physics 1922
https://www.britannica.com/biography/Niels-Bohr#ref280690 -
Henry G.J. Mosely
Discovered that elements are different due to their atomic number. He discovered 4 elements- technetium, promethium, rhenium, hafnium. https://www.britannica.com/biography/Henry-Moseley -
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Erwin Schrodinger
He used a self-made equation to calculate the wave function of a quantum mechanical system- like how an electron evolves. He won the Nobel Prize in Physics 1933. https://www.britannica.com/biography/Erwin-Schrodinger -
Electron Cloud Model
Proposed by Erwin Schrodinger
https://www.msnucleus.org/membership/html/jh/physical/atomictheory/lesson1/atomic1g.html -
Werner Heinsburg
He discovered the uncertainty principle, it states that a particle's position and momentum cannot both be known exactly. He also won the Nobel Prize in Physics in 1932. https://www.britannica.com/biography/Werner-Heisenberg -
James Chadwick
He discovered the neutron. He won the Nobel Prize for Physics in 1935. https://www.britannica.com/biography/James-Chadwick
