Rutherford gold experiment

I don't know why, but I can say that gold has low ionization energy, large atomic radius and low electronegativity. Judging from that, he found the proton because there was enough area (large radius) for the particles to go through the electrons, but the nucleus (gold nuclei are dense--79 protons) was dense enough so that he could see that there was a nucleus. If it had been an element with a smaller radius, such as aluminum, it might have been harder to see the particles go through the electrons. I haven't tried that experiment, so I don't know if I'm right.

Probably the main reason was that gold can be beat into a very thin sheet with relative ease. The original purpose was not to look at the backscatter, but to look at the alpha particles that made it through, which would necessitate a thin foil. Rutherford's gold foil was on the order of a micron thick. The backscatter experiments were basically proposed by Rutherford to keep a graduate student busy and would have used the same foil as he had been using to look at through-scatter.

interesting