Oxygène
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 | Å | Fusion heat | 0.22259 | kJ/mol | |
| Atomic radius | 0.65 | Å | 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, but this discovery was not immediately recognized, and the independent discovery by Joseph Priestley was more widely known. It was named by Antoine Laurent Lavoisier 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 carboxylic acids (R-COOH).
| Isotopes of oxygen | ||||||
|---|---|---|---|---|---|---|
| 012 0.40 msec p, 17.338 MeV N-11 |
013 8.58 msec EC, 17.765 MeV N-13 |
014 70.606 sec EC, 5.143 MeV N-14 |
015 122.24 sec EC, 2.753 MeV N-15 |
016
99.762%
Stable
|
017
0.038%
Stable
|
018
0.200%
Stable
|
| 019 26.91 sec B-, 4.821 MeV F-19 |
020 13.51 sec B-, 3.814 MeV F-20 |
021 3.42 sec B-, 8.109 MeV F-21 |
022 2.25 sec B-, 6.490 MeV F-22 |
023 82 msec B-/B-n, 11.290 F-23/F-22 |
024 61 msec B-/B-n, 11.400 F-24/F-23 |
MASS
abund. Half-life Particle, Energy Decay Product(s) |
- See also combustion -- Oxidation.
- Back to Chemistry -- Periodic table