Relative atomic mass: 1.00794 +- 0.00007

English: Hydrogen
French: Hydrogene
Croatian: Vodik
German: Wasserstoff
Italian: Idrogeno
Spanish: Hidrogeno

Atomic number: 1
Group numbers: 1
Period: 1
Standard state (20 oC): gas

Discovery: 1766 Sir Henry Cavendish (GB)
Hydrogen was discovered by Sir Henry Cavendish (GB) in 1766. The origin of the name comes from the Greek words hydro and genes meaning water and generate. It is a colourless, odourless gas which burns and forms explosive mixtures in air and reacts violently with oxidants. Hydrogen is the most abundant element in the universe. Commercial quantities of hydrogen are produced by reacting superheated steam with methane or carbon. A laboratory method for producing hydrogen is by the reaction of acids on metals such as zinc or by the electrolysis of water. Most hydrogen is used in the production of ammonia and in metal refining. It is also used as fuel in rockets. Its two heavier isotopes (deuterium and tritium) are used respectively for nuclear fusion. The price of 99.999 % pure hydrogen gas costs 200.70 /dm3 in small quantities (1 dm3) and about 2.21 /dm3 in large quantities (300 dm3).
Electronic configuration: 1s1
Formal oxidation number: -1 +1
Atomic radius: 37.3 pm

Electronegativities: 2.2
Thermal conductivity: 0.183 W/(m K)
Electrical resistivity (20 oC): - microOhm cm

Melting point: -259.34 oC
Boiling point: 252.87 oC

Heat of fusion: 0.12 kJ/mol
Heat of vaporization: 0.46 kJ/mol
Heat of atomization: 216.003 kJ/mol

Table <= 1H => 2He

ASCII Periodic Table of the Elements
29 Aug. 2017
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