In Rutherford's experiment involving the deflection of alpha particles by atomic nuclei, the fact that some of the alpha particles bombarding the thin gold foil were back-scattered, led to one of the following conclusions. It was concluded that: w) the charge of an electron is negative x) the nucleus of a gold atom carries all its charge y) most of the mass of a gold atom is in its nucleus z) the nucleus of a gold atom occupies nearly the entire space of the atom