How do atomic structures differ from one another?
Size is the obvious difference, as a result of larger nuclei (higher numbers of protons and neutrons) and more electrons (thus more orbitals are filled and overall shape is indicative of orbitals filled).
All atoms do, however, follow a similar form. Based on the Bohr-model of an atom, the general structure is the same. A nucleus (consisting of protons and neutrons) and orbiting electrons around this nucleus.
All atoms posses different numbers of protons and electrons and thus as a result will have a different physical size and different electron configurations, but ultimately will follow the same 'form' as all other atoms within the periodic table.