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500 BCE
The Alchemists
The Alchemists broke down the four main categories for chemical composition. Fire, earth, water and wind. They helped lay downs the foundation for the modern day Periodic Table of Elements. https://findanyanswer.com/how-did-the-alchemists-contribute-to-the-atom -
427 BCE
Plato
Plato was convinced that atoms were derived from the four main fundamental sections of matter, fire, water, earth and wind. He said that atoms were also in different types of shapes. https://findanyanswer.com/when-did-plato-discover-the-atom -
400 BCE
Democritus
He proposed the idea that everything that is matter was made up of tiny, almost invisible atoms. Democritus said atoms were the main building blocks of matter. https://www.britannica.com/biography/Democritus -
Robert Boyle
Robert Boyle claimed that everything was composed of tiny particles that could be distinguishable by shape and motion, and that these particles were small, but never invisible. https://www.britannica.com/biography/Antoine-Lavoisier -
Antone Lavoisier
Antone Lavoisier determined that oxygen was a very important gas, he also gave the substance it's name. He also discovered the Law of Conservation and Mass. https://www.britannica.com/biography/Antoine-Lavoisier -
John Dalton
John Dolton's theory of particle pressures, in the idea that atoms in a mixture of gases will repel each other like magnets. He said this is why many gases will behave independently. https://www.britannica.com/biography/John-Dalton -
Amedeo Avogadro
He discovered that different gases, if they have the same volume, and mostly the same temperature, the gases contain the same amount of molecules. https://www.britannica.com/biography/Amedeo-Avogadro -
Dmitri Mendeleev
He made the first classification system for the Periodic Table of Elements. He left out spaces for what he thought were unknown elements. https://www.britannica.com/biography/Dmitri-Mendeleev -
JJ Thompson
JJ Thompson discovered the electron and experimented on it. This was the first atomic particle that was discovered. https://atomictheorytimelineofscientists.weebly.com/j-j-thomson.html -
Pierre and Marie Curie
They discovered that the arrangement of an atom did not make radioactive. It was the atom itself that was radioactive. https://atomictheorytimelineofscientists.weebly.com/marie-curie.html -
Neils Bohr
Neils Bohr discovered that electrons orbit the nucleus of the atom. Similar to how planets orbit the sun. https://atomictheorytimelineofscientists.weebly.com/niels-bohr.html -
Albert Einstein
Albert Einstein mathematically proved the existence of atoms. This helped revolutionize science. https://atomictheorytimelineofscientists.weebly.com/albert-einstein.html -
Robert Millikan
Robert Millikan studied and experimented on the electric charge of the electron. https://atomictheorytimelineofscientists.weebly.com/robert-millikan.html -
Ernest Rutherford
Ernest Rutherford increased the knowledge about the atom by discovering the nucleus of the atom. https://www.britannica.com/biography/Ernest-Rutherford -
Henry G. J. Moseley
He proved that every elements identity is determined by the number of protons it has. https://www.britannica.com/biography/Henry-Moseley -
Erwin Schrodinger
He claimed that it was most likely that you could find an electron in a certain spot around the nucleus of the atom. https://www.britannica.com/biography/Erwin-Schrodinger -
Werner Heisenberg
Werner Heisenberg made the theory that electrons don't have one certain pattern they move in around the nucleus of the atom. https://atomictheorytimelineofscientists.weebly.com/werner-heisenberg.html -
James Chadwick
He discovered the neutron that along with protons, make up the nucleus of the atom. https://www.britannica.com/biography/James-Chadwick