Oxygen is an element and not a compound. A molecule of oxygen is formed by the sharing of two pairs of electrons between two oxygen atoms, leading to the formation of a double covalent bond.
Oxygen was discovered by Carl Wilhelm Scheele and Joseph Priestley in 1772. The atomic number of oxygen is 8, and its electronic configuration is 1s2 2s2 2p4. It has six valence electrons. The atomic weight of oxygen is 15.9994 atomic mass units.
Oxygen belongs to period 2 and group 16 of the periodic table of elements. It is a gas at normal temperature and pressure. The symbol of oxygen is O. It belongs to the family of elements called chalcogens.