Physical Properties

The physical properties collected in Table 7.6 reveal a clear metal–nonmetal transition running down Group 16: oxygen and sulphur are non-metals, selenium and tellurium are metalloids, and polonium is a genuine metal. Polonium is additionally radioactive, with a short half-life of 13.8 days. Every element in the group displays allotropy — existing in more than one structural form, as already seen for phosphorus in the previous group and true here as well. …