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400 BCE
Democritus/Model
Democritus said that atoms have shape,matter, and motion but have no color. -
John Dalton/Model
John Dalton thought that that everything that has matter is made up of atoms. He also thought that you can not see atoms. -
Dmitri Mendeleev
He thought of the periodic law. He created the first periodic table. Dmitri arranged the elements by their mass. -
Eugene Goldstein
Discovered the proton. He noticed rays traveling from cathode to which are now electrons. The rays were the gas part in the tube and were eventually the positive charged ions. -
J.J. Thompson
His main discovery was knowing about the electron. He said cathode rays had a negative charge. -
Ernest Rutherford
He found that atoms have a small charged nucleus with electrons around the nucleus. -
Niels Bohr
Thought energy is transferred in defined quantities. Electrons can separate and orbit around the nucleus. -
Max Plank
Discovered that hot objects have more values and other values were forbidden. Eventually, this would be the discovery of the quantum theory which means matter and energy based on the quantum mechanics. In 1919 he won the Nobel Peace prize but does not say when he found the discovery -
Robert Millikan
Robert discovered the elementary electric charge. It is a charge that is carried by electrons. He made an experiment called the oil drop to determine the density of oil. After that, he found that after multiple experiments, it was a different value every time -
Erwin Schrodinger and Werner Heisenberg
They made a model of trying to find electrons orbiting something. They also said it's impossible to see a single atom. Later made and equation of electrons moving. -
James Chadwick
James Chadwick discovered the neutrons in atoms. Neutrons are in the middle of the atom. They are part of the atomic weight and do not give off positive or negative charge.
