What did the deflection of alpha particles in Rutherford's experiment indicate?

In Rutherford's gold foil experiment, the deflection of alpha particles provided crucial evidence regarding the structure of the atom. The majority of alpha particles passed through the gold foil with little to no deflection, but a small number were significantly deflected at large angles. This observation indicated that most of the atom is empty space, and it suggested the presence of a dense central region within the atom that had a positive charge.

The positive charge in the nucleus is what causes the alpha particles to be repelled when they come close to it, leading to the observed deflection. This experiment fundamentally changed the model of the atom from a uniform cloud of positive charge (as previously thought) to one where a small, dense, positively charged nucleus exists at the center, surrounded by orbiting electrons.

Therefore, the deflection of alpha particles in Rutherford's experiment is directly linked to the existence of a positively charged nucleus within the atom. This finding was pivotal in the development of modern atomic theory, illustrating how the atom is structured with a central nucleus that contains protons and neutrons, which is surrounded by electrons.