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The alchemists were the first to use the word "element". They analyzed matter and how it forms to a chemical reaction. They also attempted to purify, mature, and perfect certain metals. -
Democritus's atomic theory was that an atom was just one sphere. -
Plato (and Aristole) proposed that matter was continuous, infinite, present in every form, and always around it. -
Robert Boyle believed that everything was composed of very tiny particles. -
Antoine Lavoisier discovered the Law of Conversion of Mass, which stated that matter cannot be created or destroyed. -
John Dalton discovered how atoms worked and made understanding chemical compounds simple. -
Amedeo Avogadro hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. -
Dmitri Mendeleev created a basic Period Table of Elements. -
JJ Thompson discovered elements through the Cathode Ray Rube Experiment. He also created the Plum Pudding Model. -
The Curies discovered "Polonium", a new element which was 400 times more radioactive than any other -
Albert Einstein mathematically proved the existence of atoms. His atomic theory revolutionized modern science. -
Ernest Rutherford performed the Gold Foil Experiment, which made him discover a nucleus present in the atom. He created the Nuclear Model. -
Henry Mosely found a link to the atomic number. He developed it into more detail. -
Niels Bohr created a model which proved that when you excite an electron by giving it energy, it jumps onto another energy level. The electrons, as a result, give off light quantum. -
Robert Millikan helped in understanding the structure of an atom. He performed the Oil Drop Experiment to find out that electrons were negatively charged. -
Werner Heisenburg contributed to the Atomic Theory through formulating quantum mechanics in terms of matrices and in discovering the Uncertainty Principle, which states that a particle's position and momentum cannot both be known exactly. -
Erwin Schrodinger theorized that the behavior of electrons within atoms could be explained by treating them mathematically as matter waves.
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James Chadwich discovered neutral charged neutrons in the nucleus.