Zusammenfassung der Ressource
The Changing Atom
- Democritus
- imagined that
atoms were
held together
with tiny
hooks
- Suggested you
could divide
matter only so
many times
- John Dalton
- All atoms of a given element are the same
- atoms cannot be divided
- atoms are tiny particles that make up elements
- atoms are different in different elements
- JJ Thomson
- Plum-pudding model
- negative electrons in a 'sea' of positive charge
- = neutral with no overall charge
- He discovered the electron
- Ernest Rutherford
- 2 of his students fired alpha
particles at a very thin piece of
gold foil
- they measured deflection (change in direction)
of the particles
- concluded that a
plum-pudding model woud
hardly deflect alpha particles
at all.
- the atoms positive charge
must be concentrated into a
volume much smaller than the
size much smalleer than itself