Electronic data		Thermal data		Steric data
Shells: 1 Orbitals: 1s1 Electronegativity: 2.2, 2.1 1. Ionization potential: 13.5984 eV 2. Ionization potential: -- eV 3. Ionization potential: -- eV Oxidation states: 1,-1 Electrical conductivity: --		Melting point: -255.34 °C Boiling point: -252.87 °C Specific heat: 14.304 J/gK Heat of fusion: 0.05868 kJ/mol Heat of vaporization: 0.44936 kJ/mol Thermal conductivity: 0.001815 W/cmK		Atomic radius: 0.79 Å Ionic radius: 1.54 Å () Covalent radius: 0.32 Å Atomic volume: 14.4 cm³/mol Density (293 K): 0.00008988 g/cm³ Crystal structure: Hexagonal

Nuclide	Abundance [%]	Mass	Spin	Halflife	Decay mode	Decay tree
1H	99.984	1.0078	1/2	--	stable	--
2H	0.0156	2.0141	1	--	stable	--
3H	0	3.016	1/2	12.3y	-	View

Legend

Name origin:	Greek: hydro (water) and genes (generate)
Description:	Tasteless, colorless, odorless gas. The most abundant element in the universe. Tenth most abundant element in the earth's crust.
Discovered by:	Henry Cavendish
Year:	1766
Place:	England
Sources:	Commercial quantities are produced by reacting superheated steam with methane or carbon. In lab work from reaction of metals with acid solutions or electrolysis.
Use(s):	Most hydrogen is used in the production of ammonia. Also used in balloons and in metal refining. Also used as fuel in rockets. Its two heavier isotopes are: deuterium (D) and tritium (T) used respectively for nuclear fission and fusion.