How did atomic theory change because of the gold foil experiment?
The concept of a dense nucleus was added to the atomic theory.
Rutherford's gold foil experiment yielded surprising results.
The theory was that the positive and negative charges were distributed throughout the atom like a fruit cake (Thompson's atomic model)
Rutherford's hypothesis was that shooting high velocity atomic particles at the atom would act like x rays yielding a picture of the structure of the inside of the atom, indicating how the particles were distributed in the atom.
The results were that most of the particles pasted through the atom with no deflection. Some that passed near the center of the atom were deflected slightly. The big surprise was that a few were bounced straight back. It was like shooting a bullet at what you thought was tissue paper and having the bullet ricochet back in your face.
The results of the experiment lead to the theory that all of the positive charge of the atom was located in the center of the atom in a dense nucleus.