How do scientists know particle numbers in atoms?

How do scientists determine the number of protons or electrons in an element when these particles can't even be visible through any microscope?How do scientists know particle numbers in atoms?
they use the scientific method.How do scientists know particle numbers in atoms?
Part theory and part experimentation. Theory dates back to early models of the atom, as well as the periodic table. Experimentation? That's thanks to particle accelerators.

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