how were alpha particles used and founded before the gold foil experiment if we didn’t know at that time that protons and neutrons existed and we didn’t know the charge of alpha particles

Question

I understood most of the rutherford experiment except how did rutherford know the properties of alpha particles when we didn’t know about protons and neutrons .

In: Chemistry

Answer 1

We knew they were positively charged, and we knew they were emitted from certain radioactive materials.

Rutherford discovered the alpha particles 9 years before his gold foil experiment in an attempt to figure out what the structure of atoms was like. This man was working on it for years.

We can tell it’s positively charged and has more mass than an electron by running it through an electric field and noting it deflects the opposite direction compared to an electron, which we had decided was negative.