The History Of Atom

The History of Atom 1. Alchemists – 500 BC • Philosopher’s Stone • Elixir of Life (Eternal Life) 2. Democritus • A Greek Philosopher • Developed the atomic theory of the universe (matter is made up of atoms that cannot be further divided; atoms are eternal and invisible) 3. Aristotle • Developed the scientific method/work 4. Isaac Newton • Formulated the laws of universal gravitation and motion • Invented the mechanical picture of the universe with small solid masses in motion 5. Antoine Lavoisier • Founder of modern chemistry • Invented the formula for conservation of matter in chemical reactions • Distinguished an element from a compound

6. Charles Augustin de Coulomb • A French Physicist • Formulated the principle of Coulomb’s Law (Governs the interaction between electric charges)

7. John Dalton • Developed the atomic theory (matter is composed of atoms) 8. William Crookes • Developed Crookes Tube (In it, cathode rays travel in straight lines and produce phosphorescence and heat when it strikes materials) 9. W.K. Koentgen • Discovered X – rays while experimenting cathode – ray tubes 10. Antoine Henri Becquerel • Discovered radioactivity when he investigated uranium 11. Curies • Discovered radium and polonium 12. J.J. Thomson • Discovered electron • Plum – pudding model of atom 13. Max Planck • Quantum Theory 14. Albert Einstein • Postulated that light was made up of different particles

15. Robert Millikan • Electric charge of electron • “Oil – drop” Experiment • Calculated the mass of electron 16. Ernest • • •

Rutherford Gold – foil experiment All atoms were in small positively charged particles Most parts of atom is an empty space

17. Henry Moseley • Charges on the nuclei of most atoms • Atomic number of an element = number of protons in the nucleus 18. Neils Bohr • Electrons moved around the nucleus in successively large orbits 19. Louis de Broglie • Electrons had a dual nature similar to both particles and waves 20. Hans Wihelm Geiger • First detected alpha molecules 21. Erwin Schrodinger • Formulated the Schrodinger wave equation to describe the behavior of electrons in an atom 22. Werner Heisenberg • Principle of indeterminacy 23. James Chadwick • Discovered neutron • Led to the discovery of nuclear fission and atomic bombs 24. Otto Hahn • Nuclear Fission 25. Lise Meitner • Together with Otto Hahn, they discovered nuclear fission 26. Glenn Theodore Seaborg • Isolated elements heavier than uranium

27. Murray Gell – Mann and George Zweig •

Idea of quarks