Electrons do not "flow" in a circuit. Electron motion and electromagnetic forces and energy in circuits are determined solely by the electromagnetic fields generated by a difference in potential. Electric current is a very useful construct. I use it myself because it is helpful. But it is not correct
Oh dear. In a conductor such as a metal, some electrons are freed from the outer atomic shell and are free to bounce around, normally at random. Their average speed is determined by the temperature. If you apply a potential difference, more electrons on average will pile up at the negative end. Complete a circuit, and there will be a slow electron drift on average from negative to positive. The electrons flow in the circuit.
