Atomic Theory Time Line

Demcritus

400

Democritus was one of the first greek philosophers to devolop an atomist theory of the universe.

Atomic Theory Time Line

Period: 400 to Jan 1, 1926

Antoine Lavoisier

Oct 23, 1777

Antoine was a french vhemist and he made up the Law of conservation of Mass and named oxygen and hydrogen

Law of conservation of Mass

Oct 23, 1789

The Law of Conservation of Mass was created by Antoine in 1789 and it states that mass can't be created or destroyed.

John Dalton

Oct 23, 1803

John Dalton discovered the existence of atoms and found the first 6.

Dalton's Atomic theory

Oct 23, 1805

Dalton's Atomic theory states that matter is made up of tiny atoms. 2nd he stated that all atoms of a given element are identical and compounds are fomed by a combination of two or more elements.

Dmitri Mendeleev

Oct 23, 1869

Dmitri was a Russian chemist who discovered the peroiodic law and developed the periodic table.

J.J. Thomson

Oct 23, 1897

J.J. Thomson, a British physicist, discovered the electron and how it had a negative charge.

Cathode Ray Tube

Oct 23, 1897

This Cathode Ray Tube was inverted by J.J. Thomson and this tub is a vacuum tube containing an electron gun and a florescent screen used to view images.

Plum Puddin Model

Oct 23, 1904

The plum pudding was created by J.J. thomson. He created it to probe the atom. he thought the electrons were like little raisins. The atom was like a plum pudding with a positive charge (1+) and mass spread all around like pudding.

Gold Foil Experiment

Oct 23, 1909

The Gold Foil Experiment was created by Rutherford and it showed how particles with a 2+ charge interacts with a piece of very thin piece of gold foil.

Robert Millikan

Oct 23, 1909

Robert Millikan was an American physicist and he discovered the measurment of an electron on tiny falling water.

Rutherford's Model

Oct 23, 1909

Rutherford was a british physicist who created the ruthford model and it showed the atom made up of a central charge surrounded by a cloud orbiting electrons.

Ernest Rutherford

Oct 23, 1911

Ernest Rutherford discovered the nuclues.

Electron Cloud Model

Oct 23, 1913

The electron cloud model was invented by Erwin Schrodinger. The cloud model represents a history of where the electron has probably been and where it's likely to be.

Henry Moseley

Oct 23, 1914

Henry Moseley was an English physicist. He used an x-ray spectrums to determine atomic numbers

Bohr Planetary Model

Oct 23, 1915

The Bohr Planetary model isa model showing an atom consisting of a small, positively-dharged nucleus orbited by a negatively-charged electrons. Niels Bohr created it.

Niels Bohr

Oct 23, 1922

Niels Bohr was a Danish physicist. He discovered the structure of the atom and how the electrons travel in an orbit around the atom's nucleus.

Erwin Schrodinger

Oct 23, 1926

Erwin Schrodinger was an Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave machanics. He formulated the wave equation and revealed the identity of his development.

Quantum Mechanical Model

Oct 23, 1926

The Quantum Mechanical Model was invented in 1926. It was mainly based on mathematics and the Quantum Theory which states that matter also has porperties associated with waves. It helps explain observations made on complex atom.

James Chadwick

Oct 23, 1932

James chadwick was an English phycisist. he discovered the neutorn. He discovered this by understanding the nulclear fission of uranium.