Here's why:
* Alpha particles are positively charged. They were fired at a thin gold foil, and most of them passed through the foil without any significant deflection. This suggested that the atoms in the gold foil were mostly empty space.
* Some alpha particles were deflected at large angles, even backwards. This was unexpected, as the alpha particles should have passed through the mostly empty atoms without much resistance.
* Rutherford explained this by proposing a model where the positive charge of the atom was concentrated in a tiny, dense nucleus. This nucleus was responsible for the large deflections observed.
Key takeaways:
* The gold foil experiment revolutionized our understanding of the atom.
* The existence of a nucleus was a groundbreaking discovery.
* It was the beginning of the modern atomic model, which continues to evolve today.
