History of the Atom

  1. Dalton - the discovery of the atom (1808)
  • Thought it was the smallest thing ever
  • Knew that all objects were made up of them
  • Thought it was just a solid sphere that made up an element
  1. Thomson - plum pudding model (1904)
  • A model where the atom had negatively charged electrons dotted around randomly inside of it
  • Theorised that the atom wasn’t the smallest object
  • Disapproved Dalton
  1. Rutherford - gold foil experiment (1908)
  • Shone positively charged alpha particles at a thin sheet of gold foil
  • Alpha particles went in random directions, hit the foil, or went straight through it
  • Showed that there were gaps in the atom and that there was something in the middle
  • Disapproved Thomson
  1. Bohr - bohr model (1913)
  • Theorised that electrons were on shells around a nucleus
  • Disapproved Rutherford