Atomic Properties of O
- Atomic Number of O
- 8
- Atomic Mass of O
- 15.9990 u
- Electron Configuration
- [He] 2s2 2p4
- Electronegativity
- 3.44
- Block
- p-block
- Group
- 16
- Period
- 2
Oxygen (O) is element 8 on the periodic table. Atomic mass of O: 15.9990 u. O is in period 2, group 16. Melting point of O: 54.36 K.Density of O: 0.00 g/cm³.
Every breath you take contains the element that keeps you alive
Essential for cellular respiration—converts glucose to energy. Makes up 65% of human body mass (mostly in water). Required by all aerobic organisms.
Discovered by Joseph Priestly, Carl Wilhelm Scheele in England/Sweden, 1774
Name origin: Greek: oxys and genes, (acid former).
A colorless, odorless gaseous element belonging to group 16 of the periodic table. It is the most abundant element present in the earth's crust. It also makes up 20.8% of the Earth's atmosphere. For industrial purposes, it is separated from liquid air by fractional distillation. It is used in high temperature welding, and in breathing. It commonly comes in the form of Oxygen, but is found as Ozone in the upper atmosphere. It was discovered by Priestley in 1774.
Oxygen exists in 3 different structural forms (allotropes), each with unique properties.
Common oxygen gas we breathe
Triatomic oxygen with distinctive sharp smell
Rare metastable form
Oxygen has 3 naturally occurring isotopes.
| Isotope | Atomic Mass (u) | Abundance | Half-Life | Decay Mode |
|---|---|---|---|---|
| 168O (O-16)Oxygen-16 isotope | 15.99491462 | 99.76% | — | — |
| 178O (O-17)Oxygen-17 isotope | 16.99913176 | 0.0380% | — | — |
| 188O (O-18)Oxygen-18 isotope | 17.99915961 | 0.2050% | — | — |
Data source: NIH PubChem (aggregated from IUPAC, NIST)
Isotopes of Oxygen have important real-world applications in science and industry.
16O is used to produce radioactive 13N via the 16O (p, 4He) 13N reaction for imaging in positron emission tomography (PET) and to study blood flow through the heart (myocardial perfusion) [94], [95]. 17O has been used as a tracer to study cerebral oxygen utilization [96]. Variations in stable oxygen and hydrogen isotopes are used in energy expenditure studies in animals and humans. The subject is administered a dose of doubly labeled water (water enriched in both 2H and 18O). Measurements of the elimination rates of 2H and 18O in the subject over time through regular sampling of body water (by sampling saliva, urine, or blood) provide information on energy expenditure because the hydrogen isotopic composition of body water is affected primarily by water loss (mainly urination), but the oxygen isotopic composition is affected by both respiration and water loss [97].
Used in steel making, welding, and supporting life. Naturally occurring ozone (O3) in the upper atmosphere shields the earth from ultraviolet radiation.
Obtained primarily from liquid air by fractional distillation. Small amounts are made in the laboratory by electrolysis of water or heating potassium chlorate (KClO3) with manganese dioxide (MnO2) catalyst.
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