Oxygen is the first element in Group 16 of the periodic table, a group of elements sometimes known as the oxygen family. Oxygen has an atomic number of 8, an atomic mass of 15.9994, and a chemical symbol of O.

Properties

Oxygen is a colorless, odorless, tasteless gas with a density of 1.429 grams per liter, slightly greater than that of air (1.29 grams per liter). Its boiling point is -297.33°F (-182.96°C) and its freezing point is -361.2°F (-218.4°C). Liquid oxygen has a slightly bluish color to it and is slightly magnetic.

Oxygen exists in three allotropic forms: diatomic oxygen, or dioxygen (O₂), atomic or nascent oxygen (O), and ozone (O₃). Atomic oxygen is a highly reactive species that forms diatomic oxygen readily and reacts with other elements and compounds easily. Ozone also tends to be unstable and break down into dioxygen and nascent oxygen...