Krypton was discovered in Britain in 1878 by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, in residue left from evaporating the components of liquid air.
Atomic number: 36
Atomic weight: 83.798
Group, period, block: 18, 4, p
Color: colorless gas, exhibiting a whitish glow in a high electric field
Classification: noble gases
Electron configuration: 3d10 4s2 4p6
Density: 3.749 g/L
Melting point: 115.79 K,-157.36 °C,-251.25 °F
Boiling point: 119.93 K,-153.22 °C,-244.12 °F
Oxidation states: 2, 1, 0
Electronegativity: 3.00 (Pauling scale)
Ionization energies: 1st: 1350.8 kJ·mol-1
Covalent radius: 116±4 pm
Van der Waals radius: 202 pm
There are six naturally occurring isotopes of krypton exist, 78Kr, 80Kr, 82Kr, 83Kr, 784Kr, and 86Kr.