P4 - Atomic structure

P4 - Atomic structure

1. Models

   • similarities
     • both balls of positive charge
     • both have electrons

2. radioactivity

   • alpha
     • charge=2+
     • penetration=only a few cm in air
     • mass=4
   • beta
     • mass=1/1832
     • charge=1-
     • penetration=a few mtrs in air /aluminium foil
   • gamma
     • charge = 0
     • mass=0
     • penetration=few metres of concrete

3. radiation

   • radiation comes from the nucleus of the atom
     • radioactive decay is descibed as random and spontaneous