Choose the correct options and explain the reason for the correct and incorrect options in the context of Ernest Rutherford's gold foil experiment:

(A) The experiment clearly showed the existence of neutrons in the nucleus.

(B) The results disproved the plum pudding model and led to the idea of a nucleus at the centre of the atom.

(C) The large deflection of a few alpha particles indicated that most of the mass of the atom and positive charge are packed into a tiny centre.

(D) The way alpha particles were deflected showed that electrons move around the nucleus.

(A) Incorrect

Reason: Rutherford's gold foil experiment did not show the existence of neutrons. Neutrons were discovered later by James Chadwick. Rutherford's experiment mainly showed the presence of a small, dense, positively charged nucleus.

(B) Correct

Reason: Most alpha particles passed straight through the gold foil, but a few were deflected. This disproved Thomson's plum pudding model, which suggested that positive charge was spread throughout the atom. Rutherford proposed that positive charge is concentrated in a small central region called the nucleus.

(C) Correct

Reason: A very small number of alpha particles were deflected through large angles or even bounced back. This showed that most of the atom's mass and positive charge are concentrated in a tiny, dense centre called the nucleus.

(D) Incorrect

Reason: The experiment did not directly show that electrons move around the nucleus. Rutherford proposed this arrangement in his atomic model, but the deflection of alpha particles mainly gave evidence for the nucleus, not for the exact motion of electrons.