What makes a big difference here regarding oscillation is whether we're talking AC or DC. In 60 cycle AC, as Edge touched on above, electrons move in a particular direction (towards the positive) for only 1/120th of a second, then they reverse direction (because the positive has moved) for another 1/120th of a second. How far they move in that time? Who knows? Probably not very far. I don't know that I'd call this motion vibration exactly, it's just changing direction 120 times a second - but call it what we will.
In DC it's a little different. The direction of the positive does not change, so electrons all travel the same direction as long as the pressure is applied. Some will sort of leap-frog from one orbit to another, some (free electrons) may simply bumble along as part of the general flow.
The lone electron in the outermost shell of a copper (or gold or silver) atom is interesting in that although it balances the atom electrically (equal number of protons and electrons), atoms in general do not like having 1 electron in the outermost orbit. The result is a quantity of free electrons in copper, unbound electrons that have simply drifted away from their orbits. Of course they might fall into another orbit, but at any given time there are lots of free electrons. That's what makes copper a good conductor.
Radar
