Symbol	Kr
Atomic number	36
Group	18 (Noble gases)
Period	4
Block	p
Classification	Noble Gas

Appearance	Colorless gas, exhibiting a whitish glow in a high electric field
Color	Colorless

Number of protons	36 p+
Number of neutrons	48 n0
Number of electrons	36 e-

From Wikipedia, the free encyclopediaKrypton (from Greek:κρυπτός kryptos "the hidden one") is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 (noble gases) elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquefied air, and is often used with other rare gases in fluorescent lamps.

Phase at STP	Gas
Density	3.749 g/cm3
Atomic weight	83.7982 u

Melting point	115.78 K -157.37 °C -251.266 °F
Boiling point	119.93 K -153.22 °C -243.796 °F
Heat of vaporization	9.029 kJ/mol

Electronegativity (Pauling Scale)	3
Electron affinity	-96 kJ/mol
Oxidation states	0, +1, +2 (rarely more than 0; oxide is unknown)
Ionization energies	1350.8 kJ/mol 2350.4 kJ/mol 3565 kJ/mol 5070 kJ/mol 6240 kJ/mol 7570 kJ/mol 10710 kJ/mol 12138 kJ/mol 22274 kJ/mol 25880 kJ/mol 29700 kJ/mol 33800 kJ/mol 37700 kJ/mol 43100 kJ/mol 47500 kJ/mol 52200 kJ/mol 57100 kJ/mol 61800 kJ/mol 75800 kJ/mol 80400 kJ/mol 85300 kJ/mol 90400 kJ/mol 96300 kJ/mol 101400 kJ/mol 111100 kJ/mol 116290 kJ/mol 282500 kJ/mol 296200 kJ/mol 311400 kJ/mol 326200 kJ/mol

Electron configuration Shorthand configuration	[Ar] 3d10 4s2 4p6
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
Electron configuration chart	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
Electrons per shell	2, 8, 18, 8
Valence electrons	8
Valency electrons	0
Bohr model	Figure: Shell diagram of Krypton (Kr) atom.
Orbital Diagram	1s 2s 2p 3s 3p 3d 4s 4p

Discovery and first isolation

William Ramsay, Morris Travers (1898)

Discovery of krypton Krypton was discovered in Britain in 1898 by William Ramsay, a Scottish chemist, and Morris Travers, an English chemist, in residue left from evaporating nearly all components of liquid air. Neon was discovered by a similar procedure by the same workers just a few weeks later. William Ramsay was awarded the 1904 Nobel Prize in Chemistry for discovery of a series of noble gases, including krypton.

CAS Number	7439-90-9
ChemSpider ID	5223
EC number	231-098-5
PubChem CID Number	5416