Difference between revisions of "Oxygen"

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==References==
 
==References==
 
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==External links==
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{{wikipedia|Oxygen}}
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*[http://www.webelements.com/oxygen/ WebElements]
  
 
[[Category:Chemical elements]]
 
[[Category:Chemical elements]]

Revision as of 12:38, 15 March 2010

nitrogenoxygenfluorine


O

S
Atomic properties
Atomic number 8
Standard atomic weight 15.9994(3)
Electron configuration [He] 2s2 2p4
Physical properties (O2)[1]
Melting point 54.8(2) K (−218.8 °C)
Boiling point 90.2(2) K (−183.0 °C)
Critical point 154.58 K, 50.43 bar
Chemical properties
Electronegativity 3.44 (Pauling)
Ionization energies[2]
1st 13.618 06 eV, 1313.943 kJ mol−1
2nd 35.1211 eV, 3388.67 kJ mol−1
3rd 54.9355 eV, 5300.47 kJ mol−1
4th 77.4135 eV
5th 113.8989 eV
6th 138.1196 eV
7th 739.3268 eV
8th 871.4097 eV
Total 2043.8432 eV
Electron affinity
140.9759(42) kJ mol−1
Atomic radii
Covalent radius 66 pm
Van der Waals radius 152 pm
Thermodynamic properties (O2)[1]
Standard entropy 205.152(5) J K−1 mol−1
Enthalpy change of fusion 0.444 kJ mol−1
Enthalpy change of vaporization 6.82 kJ mol−1
Molar heat capacity (Cp) 29.378 J K−1 mol−1
Miscellaneous
CAS number 7782-44-7 (O2)
17778-80-2 (atomic)
EC number 231-956-9
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).

Oxygen (ˈɒksɨdʒɨn) is a colourless gas which makes up about one fifth of the Earth's atmosphere. Its name comes from the Greek ὀξύς (oxys; acid, literally "sharp", from the taste of acids) and -γενής (-genēs; producer, literally "begetter").

References

  1. 1.0 1.1 Oxygen. In NIST Chemistry WebBook; National Institute for Standards and Technology, <http://webbook.nist.gov/cgi/inchi/InChI%3D1S/O2/c1-2>. (accessed 15 March 2010).
  2. Oxygen, atomic. In NIST Chemistry WebBook; National Institute for Standards and Technology, <http://webbook.nist.gov/cgi/inchi/InChI%3D1S/O>. (accessed 15 March 2010).

External links

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