Patients who waited more than 6 months to receive cataract surgery experienced more vision loss, a reduced quality of life and had an increased rate of falls compared with patients who had wait times of less than 6 weeks.
The chalcogens, the oxygen group, is located in column 16 of the periodic table. It contains the elements oxygen, sulfur, selenium, tellurium, polonium, and ununhexium (O, S, Se, Te, Po, and Uuh, respectively). These elements all contain six valence electrons and form 2- ions.
Group I Elements. The elements in this group have one electron in their outer electronic shell. Thus, each element in this group has a tendency to lose a single electron, to form a singly charged positive ion, which has the stable electronic configuration of its neighbouring Nobel Gas element in the periodic table. The elements in the group are chemically reactive.