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What evidence led scientists to discard the plum-pudding model of the atom (random arrangement of positive and negative charge) and adopt a model with a tiny, dense, positively charged nucleus?
A cathode ray bent towards a positively charged electric plate.
Emission spectra lines only showed red, green, blue, and violet for the element hydrogen.
Very few alpha particles were deflected when shot at gold foil.
Mathematical models plotted the different shaped orbitals: s, p, d, and f.