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450
Democritus(460 B.C.)
DemocritusDemocritus claimed that atoms are physically, but not geometrically, indivisible. He also stated that there is one infinite number of atoms which differ in shape and sizes. Democritus used theories to make his discovey. He said that atoms are external and indivisible and so small they can't be divided. -
450
Aristotle( 370 B.C.)
Aristotle Aristoltle did not believe in the atomic theory. Aristotle did not believe in atoms, he believed that all matter was made up of "The Four Elements" -
Heisenberg and Schrodinger
Heisenberg and SchrodingerWerner Heisenberg discovered allotropic forms of hydrogen and developed a theory of quantim physics. Schrodinger discoveredthe electron cloud model theory. They used theories from observations to make their discovery. They imagined a nucleus surrounded by distrbution and probabilities of electrons. -
Dalton
John DaltonWhat John Dalton discovered about the atom was that elements were made of the smallest particles called atoms. He also found out that all atoms for aparticular element were identical, and atoms of different elements could be torn apart by atomic weight. He also discovered , that atoms of different elements could combine in a chemical reaction to form chemical compounds in fixed rations. John Dalton used the Atomic Theory experiemnt to understand the structure of atom. -
Thomson
ThomsonThomson discovered electrons and isotopes. He discovered that electrons surrounded the nucleus of an atom. Thomson gathered evidence about the electrons from experiments. He thought the atom was a ball of positive charge. -
Rutherford
RutherfordHe discovered that the atom was not the smallest unit of mass. He discovered that atoms contained a nucleus, made of protons, neutrons and electrons. He used "The Rutherford Experiement" to make his discovery. He pictured the atom was mostly empty space. -
Bohr
BohrBohr discovered that the atom has a small positively charged nucleus. Electrons surround the nucleus and they travel around in a circular motion. He performed numerous experiments on the element hydrogen, he was famous for the Bohr model
