in the RUTHERFORDS atomic model, the electrons are orbiting around the nucleous. In the nucleus are the neutrons and protons. BOHRS atomic model, the electrons move in stable orbits around the nucleus. Each orbit present a different number of electrons. How do we identify isotopes? By the name of the chemical element followed by its mass number. The elements in the periodic table are grouped: increasing atomic number(periods), similarity in physical and chemical elements(columns). Crystals are a gorup of atoms ordered ina geometric structure.