súrefnisatónum

Súrefnisatóm is the Icelandic word for an oxygen atom. An oxygen atom is a chemical element with the symbol O and atomic number 8. Oxygen is a member of the chalcogen group in the periodic table, and it is the most abundant element in the Earth's crust and the third most abundant element in the universe. Oxygen atoms are highly reactive and readily form compounds with most other elements.

In its elemental form, oxygen exists as a diatomic molecule, O2, which is a colorless, odorless gas essential for respiration in most terrestrial life. This O2 molecule consists of two oxygen atoms joined by a double covalent bond. Oxygen also exists as ozone, O3, which is a triatomic molecule that plays a crucial role in the Earth's stratosphere by absorbing most of the Sun's ultraviolet radiation.

The atomic structure of an oxygen atom includes a nucleus containing 8 protons and typically 8 neutrons, surrounded by 8 electrons. These electrons are arranged in electron shells, with the outermost shell containing 6 valence electrons. This configuration makes oxygen highly electronegative, meaning it has a strong tendency to attract electrons from other atoms, a property that underlies many chemical reactions, including combustion and oxidation. In biological systems, oxygen is vital for aerobic respiration, the process by which organisms convert glucose and oxygen into energy, carbon dioxide, and water.