C1

• The particles in solids are ina regular lattice arrangement.
• The particles in solids don't move but vibrate around a fixed position.
• The particles in solids there are strong forces of attraction between particles.
• The particles in liquids have some force of attraction.
• The particles in liquids are free to move but tend to stick with each others
• The hotter the liquid gets, the faster the particles moves
• liquids fill the container they're in but keep the same volume
• Gas particles can move freely in all directions
• The particles in gases have little to no force of attraction.
• The particles in gases collide, and they collide more frequently when the temperature is hotter
• The particles in gases move constantly with random motion
• Physical Changes

  • changing state
  • can be reversed
  • no new substances are made
• Chemical Changes

  • not reversible
  • new products are made due to the bonds between atoms breaking causing the atoms to change place
• John Dalton - 1800s 


  described atoms as solid spheres
• JJ Thomson - 1897

  Plum Pudding Model:

  a positively charged mass with electrons randomly embedded inside, causing all the charges to cancel out
• Ernest Rutherford, Hans Geiger and Ernest Marsden

  Gold Foil Experiment:

  1. they launched positively charged alpha particles at a thing sheet of gold foil.
  2. most particles went straight through because most of the atom is empty space.
  3. some particles were slightly deflected.
  4. a small number were delfected straight backwards due to them colliding with the positive nucleus, and as 2 positive charges repel, they were deflected.
• nuclear atom


  a tiny positive nucleus with electrons around it
• Niels Bohr 


  created the idea of electron shells, and the electrons orbiting around.
• Proton - A positively charged particle found in the nucleus of an atom.
• Relative Mass of sub-atomic particles

  Proton - 1

  Nucleus - 1

  Electron - 0.0005
• Relative Charge of sub-atomic particles

  Proton - +1

  Electron - -1

  Neutron - 0
• nucleus radius - 10^-15m
• atomic radius - 10^-10m
• Mass Number - total number of protons and neutrons (the big number)
• Atomic Number - number of protons (and therefore electrons)
• Isotopes have a different number of neutrons, therefore a different mass number
• Cations are positively charged because they've lost electrons
• Ions are atoms that have lost or gained electrons to become charged
• The atomic number/proton number is the number of protons and therefore the number of electrons.
• The mass number is the number of neutrons and protons. If you take the atomic number away from the mass number, you get the number of neutrons
• Isotopes have the same number of protons but a different number of neutrons, changing the mass number ( the "big" number)