Atom
Atom is the smaller parts of an elements. On the other hand the smaller unit of a compound is molecule. It is an unit of element. Structure of an atom According to Rutherford atomic model, atom is constitutes with the particles electron revolving surrounding nucleus. Nucleus is the centre of an atom constitute with the elementary particles so called nutron and proton. All of the positive charge of an atom is concentrated into nucleus and all of the mass else. Revolving electron surrounding nucleus have no any mass. And it is negatively charged. Thr attraction between electron and nucleus is termed as electrostatic force that do not allow electorn to fly away and collapsing. Two types of electrostatic force in atom, centrifugal force and centripetal force is equal in atom.