Happi

Kemiallinen merkki: O
Järjestysluku: 8
Kategoria: epämetallit
Ryhmä: 16
Jakso: 2
Lohko: p
Moolimassa: 15,9994 g/mol
Elektronia kuorilla: 2, 6
CAS-numero: 7782-44-7
Olomuoto: kaasu
Tiheys: 1,429 g/l (0 °C, 101,325 kPa)
Sulamispiste: 54,36 K (-218,79 °C, -361,82 °F)
Kiehumispiste: 90,20 K (-182,95 °C, -297,31 °F)
Kiderakenne: cubic
Hapetusluvut: 2, 1, -1, -2
Elektronegatiivisuus: 3,44 (Pauling-asteikko)
Nimen alkuperä: oxygenium
Nimen tarkoitus: the Greek words 'oxys' and 'genes' which mean 'acid producer'
Faktoja:
- is a highly reactive nonmetallic period 2 element that readily forms compounds (notably oxides) with almost all other elements
- at standard temperature and pressure two atoms of the element bind to form dioxygen, a colorless, odorless, tas
- is the third most abundant element in the universe by mass after hydrogen and helium
- diatomic oxygen gas constitutes 20,9% of the volume of air
- all major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone
- another form (allotrope) of oxygen, ozone (O3), helps protect the biosphere from ultraviolet radiation with the high-altitude ozone layer, but is a pollutant near the surface where it is a by-product of smog
- is produced industrially by fractional distillation of liquefied air, use of zeolites to remove carbon dioxide and nitrogen from air, electrolysis of water and other means
- is used in the production of steel, plastics and textiles; rocket life support in aircraft, submarines, spaceflight and diving
- highly concentrated sources of oxygen promote rapid combustion, yet the oxygen itself is not the fuel, but the oxidant