Final answer:
Rutherford's gold-foil experiments confirmed the existence of the nucleus and led to the discovery of the proton. It also suggested the presence of another particle, which was later identified as the neutron by James Chadwick.
Step-by-step explanation:
Rutherford's gold-foil experiments proved the existence of the nucleus. The unexpected deflection of alpha particles suggested a tiny, dense center in the atom, which Rutherford concluded was the nucleus. This discovery was a significant shift from the plum-pudding model and laid the foundation for the nuclear model of the atom.
Additionally, these experiments led Rutherford to predict and ultimately discover the proton, a positively charged particle within the nucleus. The neutron was suggested by Rutherford to explain how protons in the nucleus were held together without repelling each other due to like charges. The neutron was later discovered in 1932 by James Chadwick, a student of Rutherford.