Chapter 27 Early Quantum Theory and Models of the Atom

Early Models of the Atom
Rutherford did an experiment ­ now known as
Rutherford scattering ­ that showed that the
positively charged nucleus must be extremely
small compared to the rest of the atom.
He scattered alpha particles – helium nuclei – from
a metal foil and observed the scattering angle. He
found that some of the angles were far larger than
the plum­pudding model would allow. The
expanation was that the positively charged region
had to be tiny compared to the atoms overall size.