Options (ii) and (iii) are correct because alpha particle scattering revealed a tiny, dense, positive nucleus, disproving Thomson’s model. Options (i) and (iv) are incorrect because neutrons were discovered later and deflections did not trace electron movement.
Choose the correct options and explain the reason for the correct and incorrect options in the context of Ernest Rutherford’s gold foil experiment: (i) The experiment clearly showed the existence of neutrons in the nucleus. (ii) The results disproved the plum pudding model and led to the idea of a nucleus at the centre of the atom. (iii) 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. (iv) The way alpha particles were deflected showed that electrons move around the nucleus.
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Statements (ii) and (iii) are correct because alpha particle deflections proved positive charge and atomic mass are concentrated in a tiny central nucleus, replacing Thomson’s plum pudding model. Statement (i) is incorrect because James Chadwick discovered neutrons much later in 1932. Statement (iv) is incorrect because alpha deflections were caused by nuclear electrostatic repulsion, not by the motion of revolving electrons.
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