Atomic structure

My bottom set Yr10's can never remember the particles in an atom or anything about atomic structure so tomorrow we're making paper mache balls to represent the protons and neutrons (about the size of tennis balls) and balls of Alu foil for electrons (marbles). I'm going to get each pupil to make an atom of a different element from Helium to say, Argon, and turn it into a mobile to hang from the ceiling. Each will have a periodic chart label hanging underneath and at least it should give them an idea about the size/mass of the particles and the number in an atom.