p4 Atomic structure

p4 Atomic structure

1. structure of the atom

   • nucleus
     • proton
       • mass=1
       • charge=1
     • neutron
       • charge=1
       • mass=1
   • electron
     • charge=
     • mass=close to 0

2. radio activity

   • alpha
     • mass=4
     • charge=2+
     • penetration=only a few cm in air stopped by skin, paper
     • very strongly ironising
   • beta
     • mass=tiny
     • charge=1-
     • penetration=meters in few air stopped by al foil
     • fairly ironising
   • gamma
     • mass=0
     • charge=0
     • penetration=meters in few air stopped by thick lead
     • weakly ironising
   • radiation comes from the neucleus

3. fission and fusion

   • fission splits a large neucleus into 2 neuclei
   • fusion is joining 2 small into 1 large

4. isotopes

   • atoms with the same number of protons but a different number of neutrons

5. penetration

   • alpha
     • least penatrating
     • most ionising
   • beta
     • second most penatrating
     • second most ionising
   • gamma
     • most penatrating
     • least ionising

6. Irradiation is the process by which an object is exposed to radiation.