Chemistry Doubt -

Question

In the gold foil experiment, how did Rutherford know that Radium emitted alpha particles only? Radioactive elements can emit any radiations right? So how did he know that they were only alpha particles? They could be gamma or beta too?

Answer 1

The goal of Rutherford’s foil experiment was to confirm Thomson’s plum pudding model of an atom, which at the time was thought to be like a blueberry muffin. They knew that atoms had mass and charge. Alpha particles has the most mass and charge, Beta particles have much less mass and charge and gamma particles have no charge and mass. So it was only right to use alpha particles.