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Robert Boyle
According to Boyle's law, the volume of a gas is inversely proportional to its pressure. This means that when pressure increases, volume decreases, and when pressure decreases, volume increases. He believed that everything is made up of very small particles, an idea known as atomicism. -
Dmitri Mendeleev - The Father of the Periodic Table
Mendeleev arranged the elements in order of increasing atomic weight. He predicted elements such as gallium, scandium, and germanium, leaving open spots in the table for them. -
J.J. Thomson's "Plum-Pudding" Model
J.J. Thomson used cathode rays to prove the existence of electrons. He proposed a model of the atom in which negative electrons are scattered throughout a sphere of positive charge. -
Ernest Rutherford's Gold Foil Experiment
Rutherford hit thin sheets of gold foil with alpha particles, which have positive charge. Most particles went through while others' paths bent at large angles. This proved the existence of the nucleus and that the atom was mostly empty space. -
Henry Moseley's Reorganization
Moseley realized that the elements should be arranged according to the unique atomic number, the number of protons. -
James Chadwick - Discovery of Neutrons
Chadwick pelted Beryllium with alpha particles from the natural radioactive decay of Polonium. This experiment proved the existence of neutrons and was called The Beryllium Bombardment Experiment.