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John Dalton
British scientist John Dalton, came up with the atomic theory: that elements are made up of small indivisible particles— atoms. He stated that all atoms of the same element are identical and atoms cannot be created or destroyed. -
Daltons’s Model
Encyclopædia Britannica, inc. (n.d.). John Dalton. Encyclopædia Britannica. Retrieved October 21, 2021, from https://www.britannica.com/biography/John-Dalton. -
Dmitri Mendeleev
Russian chemist, Dmitri Mendeleev, created the first periodic table of elements. He arranged the 70 then known elements by their atomic masses. -
Mendeleev’s Periodic Table
Khan Academy. (n.d.). Dmitri Mendeleev (article). Khan Academy. Retrieved October 21, 2021, from https://www.khanacademy.org/humanities/big-history-project/stars-and-elements/knowing-stars-elements/a/dmitri-mendeleev. -
J. J. Thompson
JJ Thompson was a British chemist who was best known for his discovery of the electron. He used a high vacuum cathode ray tube to discover the electron. -
Thomson’s Experiment
Admin. (2020, October 6). Cathode Ray Experiment by JJ.Thomson (CRT) - explanation & uses. BYJUS. Retrieved October 21, 2021, from https://byjus.com/chemistry/cathode-ray-experiment/. -
Ernest Rutherford
Ernest Rutherford was a New Zealand born chemist who said that an atom is mostly made up of empty space. He said that most of the mass of an atom was in the nucleus. The nucleus is positively charged and the outer part of electrons is negatively charged. He also discovered alpha and beta particles through his gold foil experiment. -
Rutherford’s Model
Encyclopædia Britannica, inc. (n.d.). Rutherford model. Encyclopædia Britannica. Retrieved October 21, 2021, from https://www.britannica.com/science/Rutherford-model. -
Niels Bohr
Niels Bohr is a very influential chemist. He was born in Denmark and was best known for making the Bohr model. One of his theories stated that atoms can only occupy certain spaces. This explained the spectral lines of Hydrogen. -
Bohr’s Atomic Model
Encyclopædia Britannica, inc. (n.d.). Bohr model. Encyclopædia Britannica. Retrieved October 21, 2021, from https://www.britannica.com/science/Bohr-model. -
Albert Einstein
He is perhaps one of the most influential scientists to ever live. Everyone has heard of him and his e=mc^2 equation. He also created the theory of relativity and the theory of quantum mechanics. -
Einstein’s Theories
Bembenek, S. (2018, March 27). Einstein and the Quantum. Scientific American Blog Network. Retrieved October 21, 2021, from https://blogs.scientificamerican.com/observations/einstein-and-the-quantum/. -
Robert Millikan
American physicist, Robert Millikan, was the first to accurately measure electric charge. He then obtained an accurate value for Planck’s constant. He became the vice chairman of the NRC and helped with war research when WW1 began. -
Louis DeBroglie
This French chemist played an important role in the discovery of quantum mechanics. He made the controversial discovery that electrons can behave as both waves and particles, thus explains their peculiar motion. -
Millikan’s Oil Drop Experiment
Encyclopædia Britannica, inc. (n.d.). Millikan oil-drop experiment. Encyclopædia Britannica. Retrieved October 21, 2021, from https://www.britannica.com/science/Millikan-oil-drop-experiment. -
DeBroglie’s Wavelength Equation
The nobel prize in physics 1929. NobelPrize.org. (n.d.). Retrieved October 21, 2021, from https://www.nobelprize.org/prizes/physics/1929/broglie/biographical/.