Oxygen

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Oxygen is a chemical element, in the periodic table. At standard temperature and pressure, oxygen is found as a gas consisting of two oxygen atoms, chemical formula O2. This oxygen is an important component of air, produced by plants during photosynthesis and is necessary for animals' respiration.

Atomic symbol O Color colorless
Atomic number 8 Density   0.0001429 g/ml
Group 16 (VI) Melting point 50.35 K
Period 2 Boiling point 90.18 K
Atomic weight 18.9994 u Vaporization heat   3.4099 kJ/mol
Bonding radius   0.73 A Fusion heat   0.22259 kJ/mol
Atomic radius   0.65 A Specific heat   0.92 J/gK
Ionization Potential 13.618 V Crystals cubic
Electronegativity   3.44 Oxide neutral
Electron configuration 1s2 2s2 2p4 See also Periodic table
Etymology from Greek oxus (acid) and gennan (generate)

Oxygen was discovered by the Swedish pharmacist Karl Wilhelm Scheele in 1771 and named by him, Antoine Laurent Lavoisier and Joseph Priestly in 1774.

Oxygen comprises about 87% of the oceans (as H2O, water) and 20% of the atmosphere (as O2, molecular oxygen, or O3, ozone). Due to its electronegativity, oxygen easily forms chemical bonds with many other elements (which is the origin of the original definition of oxidation). Famous examples are carbon dioxide (CO2), alcohols (R-OH) and carbon acids (R-COOH).


Isotopes of oxygen
012
     0.40 msec
p, 17.338 MeV
N-11
12.034417
013
     8.58 msec
EC, 17.765 MeV
N-13
13.024810
014
     70.606 sec
EC, 5.143 MeV
N-14
14.008595
015
     122.24 sec
EC, 2.753 MeV
N-15
15.003065
016       
     99.762%

Stable

15.994915
017         
     0.038%

Stable

16.999131
018         
     0.200%

Stable

17.999160
019
     26.91 sec
B-, 4.821 MeV
F-19
19.003579
020
     13.51 sec
B-, 3.814 MeV
F-20
20.004076
021
     3.42 sec
B-, 8.109 MeV
F-21
21.008654
022
     2.25 sec
B-, 6.490 MeV
F-22
22.009962
023
     82 msec
B-/B-n, 11.290
F-23/F-22
23.015695
024
     61 msec
B-/B-n, 11.400
F-24/F-23
24.020397
MASS     
     abund.
Half-life
Particle, Energy
Decay Product(s)
Isotopic Mass
See also combustion -- Oxidation.
Back to Chemistry -- Periodic table

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