P4- Atomic structure

P4- Atomic structure

1. Structure of the Atom

   • Proton
     • mass
     • charge
   • neutron

2. radioactivity

   • alpha
     • mass 4He2
     • charge 2+
     • stopped by a only few cm in air skin and paper
   • gamma
     • charge 0
     • weakly ironising
     • stopped by a few meters of thick lead and concreate
     • mass 0
   • beta
     • charge -1
     • fast moving electron
     • mass 1/1832
     • fairly strongly ironising
     • stopped by Al foil
   • isotopes
     • an atom with a different number of neutrons but the same number of proton
     • radioactive isotopes
       • nucleus is unstable
       • at a random point a unstable nucleus will break

3. history of the atom

   • democritus
   • jhon dalton
   • jj thomson