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John Dalton (1766 - 1844)
John Dalton was an English chemist. Hi ideas and research formed the atomic theory of matter. His discoveries are that elements are made of extremely small atoms, atoms are identical in size, mass, and other properties, and atoms can not subdivided, created, or destroyed. -
Lord Ernest Rutherford (1871 - 1937)
Ernest Rutherford conducted a famous experiment called the gold foil experiment. He discovered alpha and beta rays. In the experiment Rutherford shot some alpha particles some passed straight through the foil like the foil wasn't there and some got reflected back. -
J. J. Thompson (Late 1800s)
J. J. Thompson is an English scientist. He discovered the electron when he was experimenting with gas discharge tubes. He called the movement cathode rays. He found out that there was movement in the tube then he found out it was negatively charged particles-electrons. -
Niels Bohr (Early 1900s)
Neils Bohr was a Danish physicist. He proposed a model of the atom that is similar to the model of the solar system. He is saying that different energy levels can hold different number of electrons. He discovered that if he goes up a energy level it gains energy and when it loses energy it goes down a energy level. -
Democritus (460-370 B.C.)
Democritus was a Greek Philosopher who proposed the idea that matter is made of tiny, indivisible, indestructible particles called atomos. He did not have the necessary equipment to test his ideas by controlled experiments, and his ideas were eventually rejected.
