"5. Indicate whether the potential energy of the system increases (i) or decreases (d) in each of the following: a) two electrons move away from one another b) an electron is moved toward a proton c) two protons move away from one another d) a Na1+ ion moves toward a Cl1- ion Use the first letter (i or d) separated by a comma but no space. For example, use d,d,i,i to indicate that the potential energy decreases in the first two, but increases in the last two." Intuition would tell me that the answers decrease, increase, decrease, increase, but aparently thats wrong, and I have no idea how to go about this problem. Any help? Thanks in advance.