There are z protons in the nucleus of an atom, where z is the atomic number of the element. an α particle carries a charge of +2e. in a scattering experiment, an α particle, heading directly toward a nucleus in a metal foil, will come to a halt when all of the particle's kinetic energy is converted to electric potential energy. in such a situation, how close will the center of an α particle with a kinetic energy of 6.4 x 10-13 j come to the center of a gold nucleus (z = 79)?