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460 BCE
Democritus
Developed the first model of the atom. Thought atoms to be tiny measurements of matter. -
John Dalton
Developed Dalton's Atomic Theory. 5 key points including; atoms make up everything, each atom within an element is around the same size, mass, etc, atoms within differing elements are different in size, mass, etc, and finally that atoms can't be created or destroyed. (key point: combining two different atoms will form a different atom). -
Dmitri Mendeleev
Dmitri Mendeleev developed the periodic table to put elements in their order, ordered by amount of atoms. -
Eugen Goldstein
Discovered Kanalstrahlen which are canal rays of positive ions, protons, when he did experiments with cathode rays. -
J.J. Thomson
J.J Thomson discovered the electron within the atom. It was discovered with a cathode ray tube when he found that cathode rays were negatively charges. -
Max Planck
Developed the quantum theory. He helped us to better understand atomic and subatomic processes. -
Robert Millikan
Determines that there is a small amount of charge within atoms, called electrons, he also determined that their charge is quantized. -
Ernest Rutherford
Discovered that atoms have a nucleus, the center, surrounded by empty space that is circled by electrons. -
Niels Bohr
Bohr's atomic model showed the atom as a tiny nucleus (positive charge) surrounded by electrons. -
Erwin Schrödinger
Developed the quantum mechanical model of an atom. Also furthered Bohr's model, and discovered the mathematical equation for when electrons are in certain positions around the atoms. -
James Chadwick
Discovered that the nucleus of an atom contains neutrons and protons. -
Werner Heisenberg
Developed the Theory of Quantum Mechanics, this is the explanation of atomic and subatomic nature.
