The Atomic Model Time line

Lavoiser (1777)

Dec 1, 1777

http://www.angelfire.com/mb2/atoms/Lavoiser stated the Law of Conservation of Mass. He proved that matter like energy can't be destroy or created through any chemical reactions and also through his experiments he proved that matter was conserved through chemical reactions of any kind.

Charles Augustin de Coulomb (1780's)

Dec 1, 1780

http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htmCoulomb's contribution to the development of the Atomic Theory was the Coulomb's Law, which stated the force between two electrical charges or in other words charges that are alike repel but opposite charges attract.

John Dalton's Solid Sphere Model (1803)

Dec 1, 1803

http://atomictimeline.net/Dalton proposed that particles were made up of Atoms, and couldn't be split apart, created nor destroyed. Dalton believed that Atoms were solid, indivisble, indestructible spheres that were identical in size, mass, ad other properties.

Sir William Crookes (1870's)

Dec 1, 1870

http://atomictimeline.net/Crookes developed a vacuum pump that allowed him to produce Cathode-Ray tubes with small gas pressure, this helped lead his experiments to the conclusion that Cathode Rays are negatively charged.

Henri Becquerel (1896)

Dec 1, 1896

Becquerel discovered radio activity which is the uncontrollable emission of radiation. He demostrated that radiation emitted by Uranium shared characteristics with X-Rays and that it could be deflected by magnetic fields that helped proved that it contains charged particles.

Marie and Pierre Curie

Jan 1, 1898

http://www.angelfire.com/mb2/atoms/Marie and Pierre Curie studied and identified Radio Active elements. On 1898 The Curie's stated that Radio active materials caused Atoms to break down spontaneously and when the atom is broken down it causes the atom to release radiation in the form of energy and Subatomic particles

JJ Thomson's Plum Pudding Model (1898)

Dec 1, 1898

http://library.thinkquest.org/C006669/data/Chem/atomic/development.htmlJJ Thomson created the atomic structure of electrons he believed that there had to be positively charged particles that carried the mass of the Atom.He said that electrons floated around a positively charged goo that balanced negitively charged electrons.

Max Planck (1900)

Dec 1, 1900

In the 1900 Max Planck stated that energy is radiated in small descrete units called quanta to explain hot glowing matter. This helped clarify the nature of matter and energy on Atomic and Subatomic levels.

Robert Milliken (1909)

Dec 1, 1909

Robert Milliken determined the unit charge of a single electron with his Oil drop experiment using the equation:e = 1.6021892 x -10^ -19

Rutherford's Nuclear Model (1909)

Dec 1, 1909

http://library.thinkquest.org/C006669/data/Chem/atomic/development.htmlErnest Rutherford's Gold foil experiment used Alpha particles that he shot with a beam at a gold foil sheet he noticed that some alpha particles went through but some bounced back. This experiment helped him discover the positive charge and mass of an Atom that were concentrated in the center which he called it the nucleus which put all protons and electrons to orbit around the nucleus, the nucleus only made up a small fraction of the total volume of the atom.

Neil Bohr's Planetary Model (1912)

Dec 1, 1912

Bohr published a theory of atomic structure that explains how the inner orbits don't hold as many electrons as th outer orbit that can also determine the Atom's chemical Properties. Bohr also explains the way Atoms emit radiation by observing how electrons jump from outer to inner orbits and describing how it emits light.

Erwin Schodinger Electron Cloud Model (1926)

Dec 1, 1926

http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htmErwin built upon Bhor's idea's. He created the probability function The probability function describes a cloud like region where the electron is likely to be found in the denser part of an Atom. The cloud model describes the locations of where the electron has been and where it will be going next around the nucleus.

James Chadwick (1931)

Dec 1, 1931

English Physicist stated that the nucleus contained both protons and neutrons, that orbitted by negitively charged electrons. He also discovered that the neutron part of the atom has no charge but has the same mass as a proton.

Lise Meitner (1938)

Dec 1, 1938

http://www.angelfire.com/mb2/atoms/Lise Meitner was the first Austrian-swedish physicist who realized that the Atomic Nucleus could be split to form pairs of other atomic Nuclei through the process of Nuclear Fission.