My friend told me that the process of common salt preparation is fully understood.... I asked him how come there's a loss and gain of electrons in this process.. He told me because of attraction and repulsion. I asked him how does attraction and repulsion take place between charged particles... He told me that is because of exchange of virtual particles. I again asked him what is the reason that virtual particles come into play when two charged particles approach each other... He said its a given. So, how can we say that NaCl is fully understood?? Thanks.