Consider the following configuration: a grounded plane (very thin and with an infinite surface) and a positive (not important) point charge above it. What does grounded really mean? Can't I assume that it is neutral and it has infinitely many positive and negative charges? Because of the positive charge, electrons are brought on the top surface of the plane. But now is the plane neutral or "it received more electrons from the ground"? Because if it were neutral, the electric field above the plane would only depend on the point charge. Thank you.