Atomic number:8

Group numbers:16

Period:2

Electronic configuration:[He] 2s² 2p⁴

Formal oxidation number:-2

Electronegativities:3.44

Atomic radius / pm:60.4

Relative atomic mass:15.9994 ± 0.0003

 

Oxygen was discovered by Carl William Scheele (SE) in 1772. The origin of the name comes from the Greek words oxy genes meaning acid and forming (acid former). It is a colourless, odourless gas; pale blue liquid. Oxygen is extremely reactive and forms oxides with nearly all other elements except noble gases. It is the most abundant element in the earth's crust and makes up almost 21% of the atmosphere. Oxygen is obtained primarily from liquid air by fractional distillation. Small amounts are made in the laboratory by electrolysis of water. Oxygen is used in steel making, welding and supporting life. Naturally occurring ozone (O3) in the upper atmosphere shields the earth from ultraviolet radiation.

Density / g dm^-3:2000 (solid, m.p.)

 1140 (b.p.)

 1.429 (gas, 273 K)

Molar volume / cm³mol^-1:8.00 (solid, m.p.)

 14.03 (b.p.)

 22392.44 (gas, 273 K)

Electrical resistivity / μΩcm:- (20 °C)

Thermal conductivity / W m^-1K^-1:0.0263

Melting point / °C:-218.7916

Boiling point / °C:-182.95

Heat of fusion / kJ mol^-1:0.444

Heat of vaporization / kJ mol^-1:6.82

Heat of atomization / kJ mol^-1:246.785

1st ionization energy / kJ mol^-1:1313.95

2nd ionization energy / kJ mol^-1:3388.33

3rd ionization energy / kJ mol^-1:5300.51

in the atmosphere / ppm:209500

in the Earth's crust / ppm:466000

in the oceans / ppm:(H2O)