Answer: This experiment concluded that a positively charged nucleus is surrounded by mostly empty space.
Step-by-step explanation:
Rutherford gave an experiment which is known as gold foil experiment.
In this experiment, he took a gold foil and bombarded it with positively charged particles known as alpha particles. He thought that the particles will pass straight through the foil, but to his surprise, some of the particles deflected their path and a few of them returned straight back.
From this he concluded that in an atom, a small positive charge exist in the center.
Due to this positive charge, the alpha particles deflect their path and some of them returned straight back from their path. He also concluded that an atom consist of a lot of empty space.
Hence, this experiment concluded that a positively charged nucleus is surrounded by mostly empty space.