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.
Group 16 is the oxygen family. It consists of the elements oxygen, sulfur, selenium, tellurium, and polonium. Each has six of the desired eight electrons required for the octet in its highest energy level.
The oxygen atom has therefore 8 neutrons, 8 protons and 8 electrons. The number of valence electrons is equal with the group number. Since oxygen is in group 6 it means that it has 6 valence electrons. Check out the periodic table from the web site above. You will see that the number of protons and electrons are easy to determine.