Atomic Theory

Democritus

460

• CA 460 BC Abdera, Thrace
• His experiments he did were on matter.
• Democritus’s theory was that every thing is made everything up of Atoms.

Antoine Lavoisier's

Aug 26, 1743

• Antoine Lavoisier found that air was a portion of oxygen. • He later then found that hydrogen combined with oxygen to produce a dew as priestly which was reported to be water. • August 26, 1743, Paris

John Dalton

Sep 6, 1766

• Born: September 6,1766 Eaglesfield, Cumberland, England •One of his experiments was the colour blindness and he had tested this theory on his brothers because they were both colour blind and they said that they could only see the colour yellow. •All matter is made of atoms. Atoms are indivisible and indestructible. • All atoms of a given element are identical in mass and properties •Compounds are formed by a combination of two or more different kinds of atoms.

Henri Becquerel

Dec 11, 1852

• Discoverer of radioactivity.
• He put a well wrapped photographic plate in the desk and realized that the unexposed plate to light formed a pattern on the plate son to be discovered in 1896 that it was a penetrating ray that was soon called radioactivity. • When Henri Becquerel’s was doing investigations into radioactivity he discovered that uranium was left behind, indicating radiation consists of charged particles.

J.J. Thomson

Dec 18, 1856

• 18 December, 1856 Manchester, Lancashire UK
• Thomas discovered that Cathode rays were 1000 time lighter then Hydrogen atom, He called these particles Corpuscles, but later on they scientist preferred the name Electrons.
• His atomic theory was pointed at that electrons inside an atom could show that Atoms aren’t Invisible.

Max Planck

Apr 23, 1858

• April 23, 1858 Kiel, Duchy of Holstein.
• Planck mad many contributions to the theoretical physics, But the fame rested on the originator Albert Einstein’s theory of relativity.

Marie & Pierre

May 15, 1859

• They won the Noble prize in Physics for there joint research in radiation in 1903.
• They had great breakthroughs discovering radioactivity, crystallography and magnetism.
• Marie was born 7 November 1867
• Pierre was born 15 May 1859, Paris.

Robert Millikan

Mar 22, 1868

• Robert Andrews Millikan, March 22, 1868 Morrison, Illinois, U.S.
• Millikan and his graduated student used the oil drop to measure the charge of the electron this is how he figured it out.
• He determined the charge on electrons. It was John Thomson, however, who determined that electrons exist in the first place.

Ernest Rutherford

Aug 30, 1871

• 30 August 1871 Brightwater, New Zealand
• Ernest Rutherford worked with JJ in the conductive effects of X-rays on gases, then JJ and Ernest Discovered Electrons and presented this to the world in 1897.
• He said that there where more then one particle in an atom like the nucleus surrounded by a cloud of electrons.

Niels Bohr

Oct 7, 1885

• 7 October 1885 Copenhagen, Denmark.• Bohr had his focus on researching the structure of an atom. • He introduced the theory that electrons traveled around an orbit around the nucleus in an atom.

Erwin Schrodinger

Aug 12, 1887

• 12 August 1887 Vienna, Austria-Hungary
• In his early parts of his scientific career he did experiments like electrical engineering, atmospheric electricity, and atmospheric radioactivity.
• Erwin said that electrons where in shells in an orbit surrounding the nucleus.

Henry Moseley

Nov 23, 1887

• 23 November 1887 Weymouth, Dorset, United Kingdom
• Moseley watched and measured the X-ray Spectra of various chemical elements that were found by the method of diffraction’s through the crystals
• Moseley helped writing the periodic table

James Chadwick

Oct 20, 1891

• 20 October 1891 Bollington, Cheshire, England
• Chadwick discovered that previously unknown particle in the atomic nucleus, Ettore predicted it was a neutron because of the lack of electric charge.
• He helped the Atomic theory by finding Neutrons that help stabilize Protons.

Werner Heisenberg

Dec 5, 1901

• 5 December 1901 Wurzburg Bavaria, Germany
• The Matric mechanics confirmed the states between electrons and energy levels.
• His theory is that you can’t know all of the properties of an atomic theory.

Aristotle

Mar 2, 2022

• 384 BC Stagira, Chalcidice
• He has revolutionized science and the Industrial revolution.
• His discover is that he felt that the highest human faculty was the reason of its supreme activity.His theory was based on the four elements Earth, Wind, Fire & Water.