Krypton
An inert noble gas used in high-performance lighting.
Inside the Krypton atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Krypton atom step by step.
Electron configuration
[Ar] 3d10 4s2 4p6
A neutral Krypton atom has 36 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Gas
- Melting point
- 116 K (-157 °C)
- Boiling point
- 120 K (-153 °C)
- Density
- 0.003733 g/cm³
- Electronegativity
- 3 Pauling
- Atomic radius
- 88 pm
- 1st ionization energy
- 1351 kJ/mol
- Category
- Noble gases
Discovery & naming
- Discovered
- 1898
- Discovered by
- William Ramsay and Morris Travers
- Origin of name
- Greek 'kryptos', meaning hidden.
Notable uses
High-performance lighting and photographic flash lamps.
Where Krypton comes from
Several comparable sources
Both slow neutron capture in dying stars and rapid capture in explosive events contribute meaningfully.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 36
- Atomic mass
- 83.798
- Category
- Noble gases
- Group · Period
- 18 · 4
- Block
- p-block
- Shells
- 2 · 8 · 18 · 8