Er3+-doped tellurite glasses with chemical compositions (in mol%): 55TeO2-35ZnO-(5+x)PbO-2Bi2O3-(2-x)Na2O-Er2O3 with x = 0; 0.5; 1.0; 1.5 and 2.0) were synthesized and explored their physical and optical properties. Density and refractive index were measured at room temperature and other physical properties such as ionic packing ratio, field strength, polaron radius, internuclear distance and molar refraction were derived. It was found that Na2O substitution by PbO causes both refractive index and glass density increase.