History of the Atom

  • 460


    Developed the idea of atoms in 460 B.C.
    If you break a piece of matter in have again and again how far will you get until you can’t get any further
    He thought that it had to end at some point at the smallest possible bit of matter.
  • John Dalton

    John Dalton
    English Chemist, Performed experiments with various chemicals (1800s) that showed matter consists of lumpy particlesDidn’t know about their structure.
  • J.J. Thomson

    J.J. Thomson
    Discovered the electron in 1897. Proposed the ‘Raisin in the Pudding’ model.
  • Albert Einstein

    Albert Einstein
    Published the famous equation E = MC2 (1905)
  • Ernest Rutherford

    Ernest Rutherford
    Conducted an experiment to investigate the inside of the atom.
  • Robert Millikan

    Robert Millikan
    Oil drop experiment determined the mass of an electron.
    Proved Einstein’s formula correct
  • Niels Borh

    Niels Borh
    Danish physicist.
    Came up with a theory that said the electrons do not spiral into the nucleus and came up with some rules for what does happen.
    Rule 1: Electrons can orbit only at certain allowed distances from the nucleus
    Rule 2: Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. An atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit
  • Louis de Broglie

    Louis de Broglie
    Thought about particles of matter
    He thought that if light can exist as both particles and waves, why couldn’t atom particles also behave like waves?
  • Wolfgang Pauli

    Wolfgang Pauli
    Austrian physicistPredicted that an electron should spin while it orbits around the nucleus. (1924)Gave a rule governing the behavior of electrons within the atom that agreed with the experiment (Pauli’s exclusion principle)
  • Werner Heisenberg

    Werner Heisenberg
    German physicist. Matrix mechanics theory which explained the behavior of atoms based on mathematical quantities.
  • Erwin Schrödinger

    Erwin Schrödinger
    Austrian physicistAtom as a wave model (1926)psi symbol from the Greek alphabet