O.K,what sort of "atom" should we get from an uncharged nucleus?.What sort of chemistry would you expect?.Study the issue.Read Pais,"Inward Bound" and study the references at the chapter ends.Imagine a world with electromagnetism "switched-off",and then compare the proton/neutron.Are they different in such a world?,...,why is the quark-model such a good classification scheme?.Read Riordan "The Hunting Of The Quark".Study,...