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Aristotle
lived in ancient Greece in about 384B.C he belived that each -
John Dalton
He improved the atomic model in 1803. He beleived that each atom was the same shape but of different materials. -
J.J. Tompson
He improved the model in 1897. He beleived that the atom was made of protans of neutrons. he said there was 7 protons and 7 neutrons. -
Hantaro Nagaoka
he developed an early, incorrect "planetary model" of the atom. The model was based around an analogy to the explanation of the stability of the Saturn rings and a very massive nucleus. -
Robert Millikan
He helped form a better model. he helped 1910 and made a better model of the atom. -
Ernest Rutherford
He belevied that it was a very small positively charged nucleus that was orbited by electrons. He use a glass tube with metal disks and ran a current through it. -
Ernest Marsden
helped Rutherford with his experement. He helped and used the gold foil experiment to help change it. -
Niels Bohr
Bohr published his model of atomic structure in 1913. Here he introduced the theory of electrons traveling in orbits around the atom's nucleus, the chemical properties of each element being largely determined by the number of electrons in the outer orbits of its atoms. -
Louis De Broglie
he belived that the atom was a bunch of protons and neutrons. He also introduced his theory of electron waves. -
Erwin Schrödinger
he published a paper on wave mechanics and what is now known as the Schrödinger equation. In this paper he gave a "derivation" of the wave equation for time independent systems, and showed that it gave the correct energy eigenvalues for the hydrogen-like atom. This paper has been universally celebrated as one of the most important achievements of the twentieth century, and created a revolution in quantum mechanics, and indeed of all physics and chemistry. -
James Chadwick
Chadwick discovered a previously unknown particle in the atomic nucleus. This particle became known as the neutron because of its lack of electric charge. Chadwick's discovery was crucial for the fission of uranium 235. Unlike positively charged alpha particles, which are repelled by the electrical forces present in the nuclei of other atoms, neutrons do not need to overcome any Coulomb barrier and can therefore penetrate and split the nuclei of even the heaviest elements. -
Demotrous
lived in the ancient greek times about 400BC
he belived that the atoms were tinay grey balls and came up with these ideas
The atoms were different shapes but the same size. If the object was a solid that keep it shapes he thought the atom had hooks to hold it together. -
Period: to
time of changes to the atomic model
