(So named (
Greek krypton, "hidden") in
1898 by
Sir William Ramsay and
M. W. Travers,
British chemist, its discoverers, in reference to their difficulty in isolating it) A rare,
gaseous chemical element, one of the
noble gases, present in very small quantities in
air. It is basically
inert, but reacts with
fluorine and some other elements under special conditions.
Symbol: Kr
Atomic number: 36
Atomic weight: 83.80
Density (at 0°C with 101,325 pascals): 3.7 g/L
Melting point: -156.6°C
Boiling point: -152.3°C
Valence: 0
Ground state electron configuration: [Ar]3d104s24p6