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 | ||||||
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0120.40 msec12.034417 |
0138.58 msec13.024810 |
01470.606 sec14.008595 |
015122.24 sec15.003065 |
016
99.762%15.994915 |
017
0.038%16.999131 |
018
0.200%17.999160 |
01926.91 sec19.003579 |
02013.51 sec20.004076 |
0213.42 sec21.008654 |
0222.25 sec22.009962 |
02382 msec23.015695 |
02461 msec24.020397 |
MASS
abund.Isotopic Mass |
- See also combustion -- Oxidation.
- Back to Chemistry -- Periodic table