Kr
Krypton is a noble gas used in fluorescent lamps and photographic flash equipment.
Physical Properties
| Atomic Mass | 83.798 u |
| Density | 0.003733 g/cm³ |
| Melting Point | 115.79 K |
| Boiling Point | 119.93 K |
| Appearance | Colorless gas, whitish glow in discharge |
| State at Room Temp | Gas |
Chemical Properties
| Electronegativity | 3.0 (Pauling) |
| 1st Ionization Energy | 1350.8 kJ/mol |
| Electron Affinity | -96.0 kJ/mol |
| Oxidation States | +2 |
Atomic Properties
| Electron Configuration | [Ar] 3d10 4s2 4p6 |
| Atomic Radius | 88.0 pm |
| Covalent Radius | 116.0 pm |
| Van der Waals Radius | 202.0 pm |
Discovery
| Discovered By | William Ramsay, Morris Travers |
| Discovery Year | 1898 |
| Location | London, England |
| Named After | Greek 'kryptos' meaning hidden |
About Krypton
Krypton is a colorless, odorless, tasteless noble gas in trace amounts in the atmosphere. From 1960 to 1983, the meter was defined by krypton-86 emission. Krypton can form compounds with fluorine.
Uses & Applications
Fluorescent lamps, flash photography, insulating windows, and formerly used to define the standard meter.
Fun Fact
Despite its name, krypton has nothing to do with Superman -- it was named from Greek for 'hidden' in 1898, decades before the comic character.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 82 | 0.11593% | - | Yes |
| 83 | 0.115% | - | Yes |
| 84 | 0.56987% | - | Yes |
| 86 | 0.17279% | - | Yes |
Electron Configuration
[Ar] 3d10 4s2 4p6