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.
About the Group. Let's look at the other side of the periodic table now. The group of elements at the far right of the table (Group 18) is known commonly as the noble gases. They are generally chemically inert. This means that they do not react with other elements because they already have the desired eight total s and p electrons in their outermost (highest) energy level.