About

Krypton is a colorless, odorless, tasteless noble gas. Its name comes from the Greek word 'kryptos', meaning 'hidden', reflecting its rarity. It is used with other gases in energy-efficient fluorescent lamps, high-speed photography flashes, and some lasers. For a period from 1960 to 1983, the international standard for the meter was officially defined by one of its spectral lines.

Atomic Properties

Atomic Number36

Atomic Weight83.798 u

Neutrons (common)48

Electron Configuration[Ar] 3d¹⁰ 4s² 4p⁶

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶

Electrons per Shell2, 8, 18, 8

Electronegativity3

Electron Affinity0 kJ/mol

Oxidation States+2

Covalent Radius110 pm

Van der Waals Radius202 pm

Periodic Table Position

Group18

Period4

BlockP

Chemical SeriesNoble gases

Physical Properties

State at STPgas

Appearancecolorless, odorless, tasteless gas

Crystal Structurefcc

Magnetic Orderingdiamagnetic

Speed of Sound220 m/s

Thermal Properties

Melting Point115.79 K

Boiling Point119.93 K

Triple Point115.775 K

Thermal Conductivity0.009 W/(m·K)

Specific Heat0.248 J/(g·K)

Molar Heat20.786 J/(mol·K)

Heat of Fusion1.64 kJ/mol

Heat of Vaporization9.08 kJ/mol

Abundance

In Earth's Crust0 ppm

In Ocean0 ppm

In Solar System2.5 ppm

In Universe0.04 ppm

Discovery

Discovered byWilliam Ramsay & Morris Travers

Discovery Year1,898

Occurrenceprimordial

CAS Number7439-90-9

Electron Configuration

Energy

↿⇂

Isotopes of Krypton

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁷⁸Kr	77.920390	0.35%	Stable	Stable
⁸⁰Kr	79.916380	2.28%	Stable	Stable
⁸¹Kr	80.916592	Trace	229 ky	Electron Capture
⁸²Kr	81.913480	11.58%	Stable	Stable
⁸³Kr	82.914130	11.49%	Stable	Stable
⁸⁴Kr	83.911510	57%	Stable	Stable
⁸⁵Kr	84.912527	—	10.728 y	Beta Minus Decay
⁸⁶Kr	85.910610	17.3%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Krypton in our interactive viewer.

View 3D Model of Krypton