Model of the Atom Timeline

Akira M. Garsed

John Dalton Model of the Atom

  • 1830
  • His atomic theory said the elements consisted of tiny particles called atoms. It states an element is one of a kinda because all atoms of an element are identical.

J.J. Thomson Model of the Atom

  • 1897
  • Thomson discovered the electron, a negatively charged particle more than two thousand times lighter than a hydrogen atom.Thomson originally believed that the hydrogen atom must be made up of more than two thousand electrons, to account for its mass.

Hantaro Nagaoka Model of the Atom

  • 1904
  • Nagaoka rejected Thomson's model on the grounds that opposite charges are impenetrable. In 1904, Nagaoka proposed an alternative planetary of the atom in which a positively charged center is surrounded by a number of revolving electrons, in the manner of Saturn and its rings.

Ernest Rutherford Model of the Atom

  • 1911
  • In many ways, the Rutherford model of the atom is the classic model of the atom, even though it's no longer considered an accurate representation. Rutherford's model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.

Niels Bohr Model of the Atom

  • 1913
  • Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.

Louis de Broglie Model of the Atom

  • 1924
  • He believed that electrons can act like both particles and waves, just like light. He also said that waves produced by electrons contained in the orbit around the nucleus, set up a standing wave of a certain energy, frequency, and wavelength.

Erwin Schrodinger - Electron Cloud Model of the Atom

  • 1926
  • The Schrodinger model assumes that the electron is a wave and tries to describe the regions in space, or orbitals, where electrons are most likely to be found. Instead of trying to tell us where the electron is at any time, the Schrodinger model describes the probability that an electron can be found in a given region of space at a given time. This model no longer tells us where the electron is; it only tells us where it might be.

James Chadwick Model of the Atom

  • 1932
  • James Chadwick's model of the atom more effectively proved that there is a nucleus in every atom.