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600 BCE
Acharya Kanad
Acharya Kanad was an ancient Indian philosopher. He theorized that minisule matter invisible to the human eye, which he referred to as "Anu" (meaning atom in Sanskrit), were indestructible and bonded together to make up every object in the world. Although rarely mentioned in modern chemistry, it is possible that Kanad was the first person to suggest such theory, two millennia before John Dalton did. -
Marie Curie
Marie Curie was a Polish/French chemist and physicist. She was known for her research on electromagnetic waves emitted from atoms. In 1898, Curie published a paper where the term "radioactivity", where she proposed that radioactivity was an atomic property and that new elements could be discovered by measuring radioactivity. Curie and her husband Pierre discovered two elements using their proposed radioactivity theory. Her work opened a floodgate for new chemical discoveries. -
Hantaro Nagaoka
Hantaro Nagaoka was a Japanese Physicist known for his contribution to the atomic theory. When J.J. Thomson put forth the plum-pudding model in 1903, Nagaoka refuted the proposal. Instead, he suggested that electron masses orbited a positively charged central mass in the "Saturnian Model". His discovery later helped Ernest Rutherford and Niels Bohr theorize their "planetary model". -
Lise Meitner
Lise Meitner was an Austrian physicist who was known for her work in nuclear physics. In 1939, her and her nephew, Otto Frisch, proposed that neutron bombardment of uranium would result in significant energy release and form barium. They detailed the division process and coined the term "fission". Her discovery guided scientists to further studies in nuclear physics and was eventually used to create the atomic bomb, although Meitner herself was never involved in the Manhattan Project. -
Dorothy Hodgkin
Dorothy Hodgkin was a British biochemist. In 1945, she succeeded in decoding the molecular structure of penicillin. In the '50s, Hodgkin discovered the three-dimensional structure of vitamin B12, and later in 1969, discovered the structure of insulin. She was awarded the Nobel Chemistry Prize in 1964. Her discoveries greatly advanced research in biochemistry and have helped save countless lives. -
Rudolph Arthur Marcus
Rudolph Arthur Marcus is a Canadian Chemist born in Quebec. Beginning in 1956, he developed the "Marcus Theory", which demonstrated the rate of outer sphere electron transfer, a class of electron transfer. His theory was expanded to also apply to inter sphere electron transfer. In 1992, he was awarded the Nobel Chemistry Prize "for his contributions to the theory of electron transfer reactions in chemical systems". -
Ronald Gillespie
Ronald Gillespie is a chemist born in London, England. He is known for contributing to the Valence Shell Electron Pair Repulsion Theory (VSEPR). The VSEPR predicts the geometric formation of molecules based on the number of valence shell electrons in the atoms. His work has helped to accurately visualize molecules in modern chemistry, positively impacting both in research and education. -
James A. Harris
James A. Harris was an American Chemist.He worked for the Lawrence Berkeley National Laboratory where, in 1969 and 1970, him and his team discovered atoms 104 and 105 respectively. By doing so, he became the first African American to have a major contribution in discovering an atom. -
Richard F.W. Bader
Richard F.W. Bader was a Canadian Quantum Chemist born in Kingston, ON. He is best known for his contributions to the Quantum Theory of Atoms in Molecules (QTAIM). QTAIM enabled the use of quantum mechanics to physically represent properties of atoms in a molecule. Furthermore, QTAIM has wide capability for further application, and with computerization, has contributed to countless further studies.
