Question

the dimension of the atom are the order of an angstrom .thus there must be a large electric field between the proton and electrons. why then is the electrostatic field inside a conductor is zero?

Answer 1

Since the net charge of a neutral atom is zero, there is no net electric flux coming out of the atom. Hence, no electric field outside a neutral atom. This is why a conductor has no electric field of its own inside or outside due to its own atoms.