Element of the Week(11thMay-17thMay2007)

[iitaspirant2009]

Oxygen

Selected Isotopes
16Oxygen 99.76%
17Oxygen 00.038%
18Oxygen 00.21%

Atomic number 8
Chemical Series Chalcogens
Standard atomic weight 15.9994(3) g·mol−1
Electron configuration 1s2 2s2 2p4
Electrons per shell 2, 6
Magnetic ordering paramagnetic
Thermal conductivity (300 K) 26.58 m W·m−1·K−1
Speed of sound (gas, 27 °C) 330 m/s

Physical Properties
Density(0 °C, 101.325 kPa) 1.429 g/L
Melting point (-218.79 °C, -361.82
°F)54.36K
Boiling point (-182.95 °C, -297.31 °F)90.20K
Critical point 154.59 K, 5.043 MPa
Heat of fusion (O2) 0.444 kJ·mol−1
Heat of vaporization (O2) 6.82 kJ·mol−1
Heat capacity (25 °C) (O2)29.378 J·mol−1·K−1

Atomic Properties

Crystal structure cubic
Oxidation states −2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies 1st: 1313.9 kJ·mol−1
2nd: 3388.3 kJ·mol−1
3rd: 5300.5 kJ·mol−1
Atomic radius 60 pm
Atomic radius (calc.) 48 pm
Covalent radius 73 pm
Van der Waals radius 152 pm

Source- Wikipedia

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Regards
Tarun Ayitam

[Kar]

Wow!

[iitaspirant2009]

http://earthobservatory.nasa.gov/Library/Ozone/ozone_2.html

this site has some info abt Oxygen-Ozone Cycle and also about the
removal of Ozone Layer.