Timeline of Discoveries


We all know the significant discoveries that were made in the world of the atom. But, most of us don't know when they happened. So this is a timeline of all of the important events and the year that it happened.


1803

Dalton comes us with the Atomic Theory and stated that all of matter was made up of atoms. He then came up with the very first model of the atom.


1886

E. Goldstein used CRT to study "canal rays" which had magnetic properties opposite of an electron. He also discovered the proton.


1897

J.J. Thomson discovered the electron with the cathode ray tube Experiment. With his discovery, he came up with the "Plum Pudding" atomic model.


1900

Max Planck came up with Quantum Mechanics and that atoms released quanta


1900

Max Planck came up with the Quantum Theory

1905

Albert Einstein studied the photoelectric effect and applied the Quantum Theory to explain it.


1909

Robert Millikan discovered the charge of the electron with the Oil Drop Experiment.


1911

Ernest Rutherford used the Gold Foil Experiment to discover that inside of the atom, the nucleus was very dense and had a positive charge. He proposed that there was an existence of neutrons. He also discovered that the electrons were outside the nucleus.


1922

Neils Bohr said that electrons moved in a specific orbit around the nucleus.


1926

Erwin Schrodinger showed mathematically that waves can be used to describe electrons in atoms. He also determined probability location of electrons in atoms


1927

Werner Heisenberg said that it was impossible to say where the exact location and momentum of a particle at the same time. This was known as the Uncertainty Principle.


1932

James Chadwick discovered the neutron.


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