hydrogen

Name hydrogen
Symbol H
Atomic Weight 1.00794
Atomic Number 1
CAS ID 1333-74-0
Group Number 1
Group Name (none)
Period Number 1
Origin of Name Greek, hydro genes = "water forming."
Year Discovered 1766
Discovery Credits Recognized as an element by H. Cavendish at London, UK.
Class Non-Metallic
Color Colorless
Standard State Gas at 77 F & 298 K
Description Colorless, odorless gas, insoluble in water. Burns in air, forms explosive mixtures with air. Used for making ammonia, cyclohexane, methanol, etc. Proposed as a future fuel to replace petroleum. Reactions between cosmic radiation and gases in the upper atmosphere produce most of the world's natural tritium (3H) and is not found in any natural mineral due to the short half-life.

Diagnostic tests: 
The presence of hydrogen in minerals is detected by using the closed-tube test and observing the formation of colorless drops of water (H2O) on the walls of the tube when the sample is heated.

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