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442 BCE
Democritus
Democritus was the first to suggest the existence of atoms. He believed that atoms were indivisible, and indestructible. -
Antoine Lavoisier
Lavoisier created law of conservation of matter, which is that matter is conserved in a chemical reaction. -
John Dalton
John is considered the father of modern atomic theory. His theory is made up of 5 parts, matter is made up of atoms, all atoms of the same element are identical, atoms of different elements are different sizes and masses, atoms can combine and make compounds, atoms cannot be created nor destroyed. -
Dmitri Mendeleev
Mendeleev was a chemist who invented the periodic table and introduced period law. -
Eugen Goldstein
Goldstein was a physicist who explored the electrical phenomena in gases and on cathode rays. He was the first to discover canal rays. -
J.J. Thomson
In 1897, J.J. Thompson used a cathode ray tube to deduce the presence of a negatively charged particle, The Electron. Thompson believed that the electrons were like plums embedded in a positively charged “pudding,” thus it was called the “plum pudding” model. -
Max Planck
Planck thought of the quantum theory because of this he won a Nobel Prize. -
Robert Millikan
Robert constructed the oil drop experiment and discovered that electrons are negatively charged. -
Ernest Rutherford
This chemist and physicist was the first person to split the atom. He won the Nobel Prize for his theory of atomic structure and is considered to be the Father of the Nuclear Age. -
Niels Bohr
Bohr is the one that made planetary model of the atom and thought that the electrons travel in energy levels. -
Henry Moseley
Moseley was one of the first people to ever understand the concept of the atomic number. -
Werner Heisenberg
He was a theoretical physicist and a pioneer of quantum physics. -
Erwin Schrodinger
This physicist came up with the wave equation for electron movements. -
James Chadwick
James Discovered the neutron by comparing electric charges and masses of different atoms. His theory is the neutron is found in the nucleus by the proton, the neutron has the same mass as the proton, the neutron has no charge.
