Krypton

Krypton
Properties
Atomic symbol	Kr
Atomic number	36
Classification	Noble Gas
Atomic mass	83.8 amu
Other Information
Date of discovery	1898
Name of discoverer	Sir William Ramsay and M. W. Travers
Name origin	From the Greek word kryptos (hidden)
Uses	Lighting and scientific standards
Obtained from	Production of liquid air

Krypton is an element in the "noble gas" class (or "inert gas") of the periodic table. It is colorless and odorless. It is almost (but not completely) chemically inert. It has six stable isotopes.

It is noteworthy in that one of its spectral lines is used as the official scientific definition of length—1 meter is 1650763.73 wavelengths. (Prior to that, the meter was defined as the distance between two lines scratched on the "International Standard Meter stick".)