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.
Oxygen atom has the outer electronic configuration of 2S 2 2p 4, with 4 reactive electrons at its outer shell. The molecular oxygen with 0 oxidation state is highly stable due to the participation of each of two electron-pairs donated by the two atoms of oxygen. Thus, the diatomic molecular oxygen contains one sigma- and one pi-bond in its structure.