My question is what makes a conductor able to pass electricity? I know that conductors have free electrons where as insulators don't have as many but can't you just add free electrons to the insulator from a battery or other source?
I know that valence bands are the outermost 'ring' of electrons. In a conductor the electrons their are loosely bound and can easily abandon the atom. However, the outermost electrons in an insulator are strongly 'bonded'. I know it has something to do with this but I'm not sure what.