36KrKrypton83.7982[Ar] 3d¹⁰ 4s² 4p⁶
noble gas

Krypton

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.

Electronic structure

A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.

Electrons by shell
Electron configuration
3d10
4s2
4p6

18 is the [Ar] core total across three shells.

Properties

At a glance

Atomic number
36
Atomic mass
83.7982 u
Phase
Gas
Density
3.749 g/L
Melting point
115.78 K
Boiling point
119.93 K
First ionization energy
1,350.8 kJ/mol
Electronegativity
3
Electron affinity
-96 kJ/mol
Molar heat capacity
Unavailable
Period
4
Appearance
colorless gas, exhibiting a whitish glow in a high electric field

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.