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John Dalton
Dalton proposed an "atomic theory" with spherical solid atoms based on measurable properties of mass. The two flaws in this model were that atoms of the same element are not identical in mass and that atoms can be divided.
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JJ Thomson
Thomson used a CRT to experimentally determine the charge to mass ratio (e/m) of an electron (1.759 x 10^8 coulombs/gram). He also studied canal rays and found that they were associated with the proton H+. The problem with Thomson's model (also called the plum pudding model) was that he assumed that the electrons were uniformly distributed and free to rotate in rings inside a sphere of positive charge.
Picture: http://ne.phys.kyushu-u.ac.jp/seminar/MicroWorld1_E/Part2_E/P24_E/Thomson_model_E.jpg -
Marie Curie
With the help of her husband, she discovered the elements radium and polonium (and radiation alltogether). She was the first woman to receive a Nobel prize, the first scientist to win the Nobel prize twice, and the first scientist to win a Nobel prize in more than one field. In WW1, she developed portable x-ray machines. Later on, she raised money to build a hospital and lab focusing on radiology.
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Max Planck
Planck was a German scientist that developed the idea of quanta, leading to quantum mechanics. As well as work with black bodies and wavelengths. Because of this, he received a Nobel prize in physics in 1918.
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Albert Einstein
Einstein contributed to the Atomic model by proposing his theory of relativity (which calculates how the movement of molecules in a liquid can cause the Brownian motion).
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Ernest Rutherford
Rutherford stated that an atom has a dense, positively charged nucleus. In his model, the electrons move randomly in the space surrounding the nucleus. Rutherford's model wasn't entirely correct because it did not account for the properties of electrons.
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Niels Bohr
Bohr developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His model of an atom has successive orbital shells of electrons. One problem with his model is that when the uncertainty principle was published, many people thought Bohr had violated the principle.
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James Chadwick
Chadwick confirmed the existence of neutrons (which have no charge). In 1935, he received a Nobel prize for this discovery. In 1941 he wrote the final draft of the MAUD report, thus inspiring the US Government to begin serious atomic bomb research efforts.
Picture: https://sites.google.com/site/mrjhatomichistory/_/rsrc/1348296933747/james-chadwick/model-of-a-perrin-tube.jpeg -
Lise Meitner
Meitner, along with Hahn and Strassman conducted experiments to prove that heavy elements capture neutrons and form unstable products which undergo fission. This process releases more neutrons, therefore, continuing the fission chain reaction. Her discoveries in this field eventually led to the Manhattan Project. The only problem with her work is the radiation in the atmosphere her discoveries led to.
Picture: https://www.atomicheritage.org/sites/default/files/Fission%20Chain%20Reaction.png
