36
Kr
Krypton
83.798
Krypton (Kr)
Noble GasGroup 18Period 4p-block-block
Krypton (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.
Latin name: Krypton
Atomic Number
36
Atomic Mass
83.798 g/mol
Phase (STP)
Gas
Electron Config.
[Ar] 3d¹⁰ 4s² 4p⁶
General
SymbolKr
Atomic Number36
Atomic Mass83.798 g/mol
CategoryNoble Gas
Group18
Period4
Blockp-block
Electron Configuration[Ar] 3d¹⁰ 4s² 4p⁶
Valence Electrons8
Colourcolorless
Appearancecolorless gas, exhibiting a whitish glow in a high electric field
CAS NumberCAS7439-90-9
Physical Properties
Phase (STP)Gas
Density0.003733 g/cm³
Melting Point-157.37°C · -251.27°F · 115.78 K
Boiling Point-153.22°C · -243.80°F · 119.93 K
Atomic Properties
Atomic Radius88 pm
Electronegativity3 Pauling
Ionization Energy1351 kJ/mol
Oxidation States+2
Ion ChargeKr2+
Crystal Structure
Crystal Structureface-centered cubic (solid)
Abundance
In Earth's Crust0.000001%
Discovery & History
Discovery Year1898
Discovered ByWilliam Ramsay, Morris Travers
Country of DiscoveryEngland
Isotopes of Krypton
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Kr-78 | 0.355% | Stable | — |
| Kr-80 | 2.286% | Stable | — |
| Kr-81 | — | 2.29 × 10⁵ years | EC |
| Kr-82 | 11.593% | Stable | — |
| Kr-83 | 11.5% | Stable | — |
| Kr-84 | 56.987% | Stable | — |
| Kr-85 | — | 10.739 years | β⁻ |
| Kr-86 | 17.279% | Stable | — |