Hydrogen [H] (CAS-ID: 1333-74-0) locate me
An: 1 N: 0 Am: 1.00794
Group No: 1  Group Name: (none)
Block: s-block  Period: 1
State: gas at 298 K (the lightest gas known)
Colour: colourless Classification: Non-metallic
Boiling Point: 20.268K (-252.87'C)
Melting Point: 14.01K (-259.14'C)
Density: 0.08988g/cm3
Shell Structure diagram | Atomic Radius diagram
Isotopes | More Info
Discovery Information
Who: Henry Cavendish
When: 1766
Where: England
Name Origin
Greek: hudor (water) and gennan (generate)
Sources
Found chiefly combined with oxygen in the form of water, also found in mines and oil and gas wells. Stars contain a virtually unlimited supply hydrogen and in the universe, hydrogen is the most abundant element (hydrogen makes up 75% of the mass of the visible universe and over 90% by number of atoms.).
Uses
Hydrogen's uses include: being used in the production of ammonia (NH3), ethanol (C2H5OH), hydrogen chloride (HCl) and hydrogen bromide (HBr); the hydrogenation of vegetable oils; hydrocracking, hydroforming and hydrofining of petroleum; atomic-hydrogen welding; instrument-carrying balloons; fuel in rockets; and cryogenic research. Its two heavier isotopes, deuterium (D) and tritium (T), are used respectively for nuclear fission and fusion.
Hydrogen fuel cells are being investigated as mobile power sources with lower emissions than hydrogen-burning internal combustion engines. The low emissions of hydrogen in internal combustion engines and fuel cells are currently offset by the pollution created by hydrogen production. This may change if the substantial amounts of electricity required for water electrolysis can be generated primarily from low pollution sources such as solar energy or wind. Research is being conducted on H2 as a replacement for fossil fuels.
Notes
Hydrogen is a tasteless, colorless, odorless and extremely flammable gas, it is also the lightest chemical element.
At standard temperature and pressure, hydrogen exists as the diatomic gas, H2, with a boiling point of 20.27 K, and a melting point of 14.02 K. Under extreme pressures, such as those at the center of gas giants, the molecules lose their identity and the hydrogen becomes a metal (metallic hydrogen). Under the extremely low pressure in space - virtually a vacuum - the element tends to exist as individual atoms, simply because it is statistically unlikely for them to combine.
A unique property of hydrogen is that its flame is nearly invisible in air.
Images
Hydrogen burns with a clean white flame Hydrogen burns with a clean white flame