In Rutherford's gold foil experiment, what result contradicted the plum pudding model's prediction?

1. The plum pudding model predicted only slight deflection of the high-energy alpha particles. 2. Instead, alpha particles occasionally scattered to large angles, and some even bounced straight back. 3. Most particles did pass through largely undeflected, but it is the rare large-angle scattering that was unexpected. 4. The foil did not melt, and alpha particles do not turn into electrons in this experiment. 5. So the occasional large-angle and backward scattering is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 22 "The Atom", section 22.1 The Structure of the Atom_