Elements of the serial number: 8
Element symbol: O
Element names: oxygen
Elements of atomic weight: 16.00
Element types: non-metallic
Discovery process:
in 1773, Sweden's Schoeller decomposition of nitrate and the use of concentrated sulfuric acid and manganese dioxide have also obtained the role of oxygen.
Element description:
Under normal conditions was colorless, odorless and tasteless gas. Density of 1.429 grams / liter, 1.419 grams / cm 3 (liquid), 1.426 grams / cm 3 (solid). Melting point -218.4 ℃, boiling point -182.962 ℃, valence 2. Ionization energy for electron volts 13.618. In addition to inert gas outside of all chemical elements can form compounds with oxygen. Most elements in the oxygen atmosphere can be heated to generate oxides. There is lot of elements can form more than one oxide. Oxygen molecules at low temperatures can form hydrated crystals O2.H2O and O2.2H2O, the latter the more volatile. Oxygen solubility in the air are: 4.89 ml / 100 ml of water (0 ℃), are the basis of life in the water. Oxygen abundance in the earth's crust rank first. Dry air contains 20.946% volume of oxygen; water has 88.81% weight of the composition of oxygen. 16O besides, there are 17O and 18O isotope.
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