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Henry Cavendish discovers Hydrogen
SourceA colourless, odourless gas that burns and can form an explosive mixture with air. -
Dalton's Atomic Theory
John Dalton proposes his theory that states that matter is composed of atoms and that all atoms of the same element re identical. He also discovered that atoms can be distinguished by their weights, as well as the fast that they cannot be created or destroyed. (Source ) -
Periodic Table Constructed
Dmitri Mendeleev is credited as the father of the periodic table, after presenting his classification of elements. However, many other scientists have also made contributions towards it. ( Source ) -
Discovery of the Proton
Eugen Goldstein discovers positivley charged particles in an experiment that involved forcing an electric current through a vacuum tube. ( Source ) -
Thomson - Discovers Electrons
Suggests a model of the atom in which he found "bodies much smaller than atoms" He discovered the electron in a an experiment designed to study the electric discharge in a high-vacuum cathode-ray tube. He suggested a model of the atom as a sphere of positive matter in which electrons are positioned by force.Source -
Mass of Electrons Discovered
Robert Millikan uses an oil-drop testcharge to mass ratio of an electron, and eventually find the mass. ( Source ) -
Ernest Rutherford
SourceHe describes the atom as having a small possitively chargered center surrounded by negitve orbiting electrons. -
Bohr Model
source The Bohr model is also known as the "planetary model" and is not completely correct but it's still a sufficient source. It was developed by Neil Bohr, who depicted the atom as a small positively charged nucleus surrounded by electrons. -
Neutron Discovered
(Source) James Chadwick makes on of the most important scientific dicoveries of the twentieth century, when he disovers particles in the nucleus without a charge, known as neutrons.
