Atomic Structure Timeline

Aristotle

322

One of two most important philosiphers of ancient science.
His writings on logic, metaphysics, ethics and political philosophy, shaped the entire history of Western philosophy.

Democritus

460

If it werent for Democritus, there would be no modern atomic theory. Democritus believed that the atoms would fit together like velcro, they could only break apart at the seams

Antoine Lavoisier

Jan 3, 1778

Discovered the role oxygen plays in combustion. He recognized and named oxygen and hydrogen.

Joseph Louis Proust

Jan 4, 1794

Published his Law of Defenite Proportions. Law states that a compound is composed of exact proportions of elements by mass.

John Dalton

Jan 5, 1794

1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a rearrangement of atoms.

Ernest Rutherford

Aug 30, 1821

Ernest Rutherford is best known as a central figure in the study of radioactivity and a leader in the exploration of nuclear physics.

Michael Faraday

Nov 4, 1831

Discovered electromagnetic induction. These experiments form the basis of modern electromagnetic technology.

Robert Milkan

Mar 22, 1868

Robert Milkan is best known for his work on the photoelectric effect and measuring the charge of the electron.

Niels Bohr

Oct 7, 1885

Bohrs theory was the discovery of electrons and radioactivity that led to different models of the stucture of the atom.

Erwin Schrodinger

Aug 12, 1887

Discovered groundbreaking wave equation for electron movements. Awarded 1933 nobel prize in physics.

Louis DeBroglie

Aug 15, 1892

Ideas were a basis for developing the wave mechanics theory. This theory has greatly improved knowledge on the physical nature of the atomic scale.

Marie & Pierre Curie

Nov 8, 1895

Known for their pioneering work in the study of radioactivity. Led to their dicovery of the elements radium and polonium.

Henri Becquerel

Nov 6, 1896

Used natural fluorescent minerals to study the properties of x-rays.
Proved that the uranium emitted radiation without an external source of energy such as the sun. Becquerel had discovered radioactivity.

J.J. Thompson

Jan 6, 1897

discovered the electron. Thomson discovered the electrons and it was proved that atoms were made up of protons, electrons and neutrons.

Max Planck

Nov 3, 1900

Discovered the equation E=Nhf, with E=energy, N=integer, h=constant, f=frequency.

Albert Einstein

Nov 5, 1916

introduces general theory of relativity. Regarded as the most remarkable scientific contribution of the 20th century.

James Chadwick

Nov 7, 1932

Proved neutron theory. Studied the beryllium radiation with an ionisation counter and a cloud chamber.

Glen T Seaborg

Nov 4, 1941

Discovered the element that makes atomic bombs explode. Awarded nobel prize beofre the age of 40.

Lise Meitner

Nov 4, 1945

Worked by side of Otto Hahn. Gave the first theoretical explanation of the fission process.

Otto Hahn

Nov 4, 1968

German chemist. Discovered nuclear fussion.