what do you think an atom is made up of? what part of the atom caused the particles to bounce back?
An atom is made up of three main subatomic particles: protons, neutrons, and electrons. Protons are positively charged particles located in the nucleus (center) of the atom, while neutrons have no charge and are also found in the nucleus. Electrons, on the other hand, are negatively charged particles that orbit around the nucleus in energy levels.
When it comes to the phenomenon of particles bouncing back, this refers to the famous experiment conducted by Ernest Rutherford called the Rutherford scattering experiment. In this experiment, Rutherford shot alpha particles (positively charged particles) at a thin gold foil. He expected the alpha particles to pass straight through the gold foil with very minimal deflection.
However, what Rutherford observed was quite surprising. Though most of the alpha particles did pass through, some of them bounced backwards or were deflected at different angles. This unexpected result led to the discovery of the atomic nucleus.
The reason for the bouncing back of the alpha particles was due to a highly concentrated positive charge in a small region of the atom, called the nucleus. Since alpha particles are also positively charged, when they encountered the concentrated positive charge of the nucleus, they experienced repulsion and were either deflected or bounced back.
So, to summarize, it was the positive charge of the atomic nucleus, specifically the protons, that caused the particles to bounce back in the Rutherford scattering experiment.