Element 36
Krypton (Kr)
Krypton (Kr) is element 36 of the periodic table, a noble gas in period 4, group 18 (p-block) with an atomic mass of 83.798 and is a gas at standard conditions.
At a glance
- Atomic number
- 36
- Symbol
- Kr
- Atomic mass
- 83.798 u
- Category
- Noble gases
- Period
- 4
- Group
- 18
- Block
- p-block
- Phase at STP
- gas
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
- Shorthand configuration
- [Ar] 3d10 4s2 4p6
- Electrons per shell
- 2, 8, 18, 8
- Oxidation states
- 0, +2
Physical properties
- Melting point
- 115.79 K
- Boiling point
- 119.93 K
- Density
- 0.003733 g/cm3
- Phase
- gas
Atomic properties
- Electronegativity (Pauling)
- 3
- Atomic radius
- 88 pm
- Covalent radius
- 116 pm
- Van der Waals radius
- 202 pm
- First ionization energy
- 1351 kJ/mol
- Electron affinity
- 0 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Kr-84 | 83.9115 | 57% | Stable |
Common uses
- Lighting
- Lasers
- Photography
- Insulation
Discovery
- Year
- 1898
- Discovered by
- William Ramsay, Morris Travers
- Country
- England