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Antoine Lavoisier
Antoine Lavoisier performed many experiments to try to prove the law of conservation of mass. He performed chemical reactions to show that no mass was lost or gained. This helped show that atoms aren't created or destroyed in chemical reactions, and gave some merit to John Dalton's theory on how atoms are invincible. Antoine Lavoisier. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Antoine-Lavoisier/106472#218479.toc -
John Dalton
John Dalton provided the base of atomic theory. In 1803, he proposed his theory about atoms. His theory had five main points, everything was made of atoms, which were invincible, all atoms of an element were identical, atoms of different elements have different weights and chemical properties, and all compounds were made of whole ratios of different elements. John Dalton. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/John-Dalton/28616 -
Michael Faraday
Michael Faraday performed many experiments to show that electricity wasn't a fluid, but was something else. As a result, he formed many compounds by running electricity through solutions of different chemicals in water. This helped to show that electricity had some sort of relation to atoms. Michael Faraday. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Michael-Faraday/109756#26080.toc -
J.J. Thomson
Just like John Dalton, J.J. Thomson was an influential figure who helped expand humanity's knowledge of atoms. In 1897, he was the first person to propose that electrons were tiny, electrically charged particles that were a part of all matter. J.J. Thomson. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/JJ-Thomson/72205 -
Marie & Pierre Curie
Marie & Pierre Curie were monumental figures in the study of radioactivity, as they were the ones to discover it. They discovered both radium and polonium, which were both radioactive. These discoveries led them to find more radioactive elements. Their discoveries helped lead the way into more research on why certain isotopes were radioactive and the nature of radiation. -
Max Planck
Planck discovered Planck's constant in 1900. It was very useful for atomic theory because it could be used to determine the charge of an electron and Avogadro's number. Max Planck. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Max-Planck/108525 -
Albert Einstein
In 1905, Einstein published four papers, one of which being very important to atomic theory. He published a paper which was one of the first pieces of experimental proof that atoms exist. He was able to prove that atoms exist by analyzing the motion of particles in still water. Albert Einstein. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Albert-Einstein/106018#256584.toc -
Robert Millikan
Robert Millikan was a professor that was set on finding the electric charge of an electron. He began his experiments in 1909, performing his oil-drop experiment, and using his results to conclude that each drop of oil had simple multiplies of the charge of an electron. In 1916, he used these results to also find the exact value of Planck's constant. Robert Millikan. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Robert-Millikan/52732 -
Ernest Rutherford
Rutherford's accomplishment that relates most to atomic theory is his discovery of the Rutherford model of the atom. After seeing that some alpha particles were turned 90 degrees from their original direction when they hit foil, he proposed that atoms had most of their mass in the center, electrons orbiting, and being mostly empty. Ernest Rutherford. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Ernest-Rutherford/109507 -
Niels Bohr
Niels Bohr contributed to atomic theory by proposing his idea to the atomic model. The Bohr model proposed that electrons had strict orbits around the nucleus instead of just moving around randomly, like in Rutherford's model. Niels Bohr. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Niels-Bohr/106088#280690.toc -
Louis DeBroglie
Louis DeBroglie was a French physicist who helped improve humans understanding of the atom and atomic particles. He had a theory that some particles, such as electrons, have wavelike properties and particle-like properties. His theory helped develop the next atomic model. Louis de Broglie. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Louis-de-Broglie/16585 -
Ernest Shrodinger
Shrodinger used the work of Louis DeBroglie to develop his own theory on how atoms worked, and was able to create Schrodinger's equation and his own atomic model. His model represents an atom with a nucleus and a cloud surrounding it, called the electron cloud. Erwin Schrödinger. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Erwin-Schr%C3%B6dinger/66219 -
Werner Heisenberg
In 1927, Heisenberg developed the uncertainty principle, which helped develop our understanding of electrons. Due to the uncertainty principle, we can't know both the position and energy of an electron. This helped fortify the idea of an electron cloud because we wouldn't know where the electrons are. Werner Heisenberg. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Werner-Heisenberg/106280#279991.toc -
Enrico Fermi
Enrico Fermi, with some colleagues, shot neutrons at many elements and recorded what they observed. They were creating many different isotopes of different elements and found that the slower a neutron moves, the better it would be at bombarding an element. Enrico Fermi. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Enrico-Fermi/34053 -
Leo Szilard
Leo Szilard was an American physicist who developed the first method of separating isotopes. This helped develop the idea of nuclear chain reactions and eventually, the atom bomb. He also worked on the Manhatten Project and the first sustained nuclear chain reaction. Leo Szilard. (2020). In Encyclopædia Britannica. Retrieved from https://academic.eb.com/levels/collegiate/article/Leo-Szilard/70806
