Ideas About Atomic Structure

Dalton's Model

• Atoms are solid, indvisible balls
  

The Electron

• Experiments with electrolysis showed that atoms could form ions
  
• The plum pudding model was developed - atoms were a positively charged sphere with negative electrons embedded within it

The Nucleus

• Rutherford fired alpha particles at a thin sheet of gold and found that most passed through but some were deflected backwards
• The nuclear model of the atom explained this evidence

Atomic Number

• Moseley discovered that atomic number is what determined which element an atom is
  

The Neutron

• Chadwick found that uncharged particles (neutrons) were released when he bombarded a thin sheet of beryllium with alpha particles
  

The Bohr Model

• This model describes electrons being in fixed orbits around the nucleus
  
• This explained why electrons didn't crash into the nucleus