Electrical conduction is due to the large number of free electrons present in good conductors like copper, silver, gold, and aluminum, rather than electrons bound to the atoms of the material in electron shells.
Basic answer.
Basically, the Electron shells in an insulator are complete, they are not prone to accepting external electrons or donating any of theirs. As such they aren't waystations for electrons...
Color is the way light reflects off of a certain object. Certain colors can retain heat better, like black since it absorbs light. White reflects light, and is therefore cooler. This is also useful...