• 200

    440 BC-Democritus

    He named the atom and said the atom could not be cut forever.
  • 201

    300 BC-Aristotle

    He disagreed with Democritus and believed that atoms could be cut.
  • Dalton

    He said all substances are made of atoms, which are small particles and atoms cannot be divided, created, or destroyed. He said atoms are alike in the same elements and different in different elements. He said atoms can make new substances if they are joined together.
  • Thomson

    He said there are particles inside of atoms, which could be divided. He named the negative charges, electrons.
  • Rutherford

    He discovered that atoms are mostly empty space with a small part of highly dense matter.
  • Rutherford

    He described atoms with a dense positive nucleus in the center of the atom.
  • Bohr

    He said that electrons move along on energy levels, jumping from one level to another level.
  • Schrodinger & Heisenberg

    They said that electrons do not travel along on paths, but in electron clouds.