C1 - Atomic Structure

• What is an atom?

  The smallest part of an element that can exist
• What is Dalton's model of the atom?

  atom as solid spheres that could not be divided into smaller parts
• What is the plum pudding model of the atom?

  Spheres of positive charge with negative electrons embedded in it - J.J Thomson in 1897
• What did Rutherford discover in the Gold Foil experiment?

  • The Nucleus
  • Orbiting negative Electrons
  • As some alpha particles were deflected by the gold foil - this proved that an atoms mass and positive charge must be concentrated into one small space
• Describe the Nuclear Model of the atom.

  Dense Nucleus with electrons orbitting it.
• What did Niels Bohr discover?

  • Electrons must orbit at set distances in certain fixed energy levels called shells.
  • Not all electrons in an atom will have the same amount of energy depending on their distance to the nucleus.
• What did James Chadwick discover?

  There are neutral particles called neutrons in the nucleus of the atom.
• What is an Element?

  Substances made of one type of atom
• What is a Compound?


  Substances made of more than one type of atom chemically joined together
• What is a mixture?


  Two or more substances not chemically bonded
• What are Isotopes?

  Atoms of fhe same element with different numbers of neutrons/atomic mass
• What is relative mass?

  The average mass of all the atoms of an element.