At a macroscopic level it appears that when two objects collide, they physically interact and the atoms touch. However the charges of the electrons actually repel one another and they don't physically touch. Correct? A neutron however has no charge so what happens when a neutron collides with an atom or another neutron? Does a collision occur because of mass or just repulsion from charge? Are neutrons just absorbed when they collide with light stable elements? Thanks in advance.