# Single electron in conductive cavity

It is a basic result in electrostatics that a charge $$q$$ in an arbitrary cavity of an ideal conductor will generate a total charge $$-q$$ on the surface of the cavity in such a way that the electric field is cancelled outside the the cavity (but only within the conductor). However, if the charge $$q$$ is the charge of an electron, and therefore the fundamental quantum of charge, how can opposing charge arrange itself in a symmetric way? Is the field cancelling nature of ideal conductors only valid when the amount of charge in play is large enough that quantization of charge is negligible?

• What kind of conductor with small amount of free charges are you thinking about? Note that electric field in the bulk of the conductor is subject to lattice-period oscillations anyway, so as the amount of free charge goes down, the concept of the mean electric field inside the conductor becomes less meaningful to the point of unusefulness. – Ruslan Jul 10 at 16:43