Final answer:
Rutherford's gold foil experiment revealed that the atomic nucleus contains the majority of the atom's mass and has a positive charge, as deduced from the deflection and reflection of positively charged alpha particles.
Step-by-step explanation:
Rutherford's gold foil experiment led to significant insights about the atomic structure. When Rutherford directed alpha particles at a sheet of gold foil, he observed that most of the alpha particles passed straight through the foil, which indicated that atoms are mostly empty space. However, some alpha particles were deflected at large angles, and a few even rebounded, implying a small, dense center in the atom. This led to the conclusion that the atomic nucleus contains almost all of an atom's mass. Furthermore, since alpha particles are positively charged and like charges repel, the deflections suggested that the nucleus itself must possess a positive charge to repel the alpha particles so forcefully. The atomic nucleus was thus understood to be a positively charged, dense core responsible for most of the atom's mass, surrounded by a much larger volume of space occupied by electrons.