Theory of atomic structure has changed over time.
19th century- John Dalton described atoms as solid spheres and said that different spheres made up different elements.
1897- JJ Thomson concluded that they weren't solid spheres. Measurements showe that an atom must contain even smaller particles (eg. electrons) - changed to plum pudding model.
Plum Pudding model= ball of postive charge with electrons stuck in it.
1909- Rutherford proved plum pudding was wrong.
Alpha particle scattering experiments. Fired positively chaarged alpha particles at…