Summary
Highlights
The Plum Pudding Model00:00:06
Before the discovery of electrons in 1897, atoms were thought to be indivisible spheres. The discovery of electrons led to the Plum Pudding model, where an atom was described as a ball of positive charge with negative electrons embedded within it.
The Alpha Scattering Experiment00:01:18
To test the Plum Pudding model, scientists conducted the alpha scattering experiment. They fired positively charged alpha particles at a very thin gold foil. Most particles passed straight through, some were deflected, and a few bounced straight back.
Conclusions and the Nuclear Model00:02:27
The experiment's results revealed that atoms are mostly empty space, the center of an atom has a positive charge, and this central part contains most of the atom's mass. This led to the development of the nuclear model, where a tiny, dense, positively charged nucleus is at the atom's center, with electrons orbiting in mostly empty space.