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370 BCE
Democritus
His model was a sphere. It had no protons,neutrons, or electrons. He created the first atomic model helping people start to realize it . -
Antoine Lavoiser
He started to name some of the elements like oxygen opposed the phlogiston theory. He also helped write some of the metric system and wrote the first bug list of elements. -
John Dalton
In 1803 John Dalton made his atomic theory stating, 1) All matter is made of atoms. Atoms are indivisible and indestructible. 3) Compounds are formed by a combination of two or more different kinds of atoms. -
Dmitri Mendeleev
He had the idea to list 63 of elements by their atomic mass into the periodic table. He made the lay out/set up of the periodic table. -
Eugen Goldstein
He contributed to the study of cathode rays. He discovered protons with experiments he had with cathode rays which would knock electrons of atoms and attracts them to a positively charged electrode. -
J.J. Thompson
In 1897 Experiment to show that cathode rays were electrically charged. The cathode ray tube by which J.J. Thomson demonstrated that cathode rays could be deflected by a magnetic field, and that their negative charge was not a separate phenomenon. -
Max Planck
Was a physicist that came up with quantum theory of energy. His work was based off atomic and subatomic process. -
Robert Millikan
He had a experiment "oil drop" and this helped find out the charge of the electron which helps us better understand the atom. -
Ernest Rutherford
In 1911 rutherford had contributed field of radioactivity and nuclear physics. He discovered alpha and beta rays. -
Niels Bohr
The Bohr model of the atom in 1913 and what parts of the atom had what charge and how electrons orbited the atom. -
Erwin Schrodinger
While looking at the Bohr model he use mathematical equations to find exactly were the electrons certain position is this is known as quantum mechanical. -
Henry Moseley
He was a physicist and justified the atomic number which came from his experiment of X-ray spectra. -
James Chadwick
In 1931 Chadwick bombarded atoms of beryllium with alpha particles and received a strange form of radiation. The particles had a neutral change and and had the approximate mass of a proton. -
Werner Heisenberg
Added to quantum theory!
