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 group number of an element in the periodic table is the same as the number of electrons in its outer shell. An element in group 1 has 1 electron in its outer shell. An element in group 2 has 2 electrons in its outer shell. An element in group 7 has 7 electrons in its outer shell. An element in group 0 has a full outer shell. The number of electrons in the outer shell gives the element its chemical properties and controls its chemical reactions.