I only have applied courses of quantum physics, so in my text book fundamentals are only briefly mentioned. In my text book the following is said of the Pauli principle: I was wondering if someone can tip the veil of these arguments a little bit. Obviously, spin has a lot to do with it. I was wondering if, with similar arguments, it is possible to explain why photon emission is a common occurence in energy exchange. I mean, what makes photons so special; the fact that they have spin 1? I was wondering whether people are getting any further in making something similar to Mendelejew's table, but for subatomic particles : that is, to show how behavior can be derived based on the number of types of fermions, bosons, etc. in a system. I haven't had any subatomic physics yet, so please don't overquark me with your input. Thanks.