1. Imagine a universe where electrons and protons have positive and negative electric charges, respectively. Could an atom consisting of one electron and one proton exist in this universe? 2. None. 3. My first thought was that such an universe already exists (ours) since an atom with a negatively charged proton and a positively charged electron is antihydrogen, which does exist but is very rare. However, my prof also wrote me the following: Think about whether a positive electron and a negative proton can form an atom in this different universe. Question does not mention anything about antimatter.