The dimensions of an atom are of the order of an Angstrom. Thus there must be large electric fields between the protons and electrons. then Why the electrostatic field inside a conductor zero?

Explanation

The protons and electrons are bound into a t atom with distinct and independent existence and neutral in charge. Electrostatic fields are caused by the presence of excess charges. But there can be no excess charge on the inter surface of an isoolated conductor. so, the electrostatic fields inside a conductor is zero despite the fact that the dimensions of an atom are of the order of an angstrom.