Ernest Rutherford

Rutherford discovered that if an atom was onlt positively charged than in his famous experiment the golg foil experiment. Were he shot a stream o atoms at a piece of gold foil. The therory was that the atoms + charged if it was then they would pass through thefoil but they didn't they bonced of in differnt directions.This is how Rutherford discoverd the neucleos. That is filled with the + charged proton and the no charge neutron. It was discovered in 911.