Xenon (symbol Xe, atomic number 54) is a heavy noble gas used in high-intensity lamps and ion thrusters. It is classified as a noble gas and sits in group 18, period 5 of the periodic table.
Overview
Xenon is the chemical element with atomic number 54 and the symbol Xe. With a standard atomic weight of 131.29, it is a noble gas. In the periodic table it occupies group 18 and period 5, and under standard conditions it is normally a gas. Xenon is a heavy noble gas used in high-intensity lamps and ion thrusters.
Atomic structure
An atom of Xenon has 54 protons in its nucleus and, when neutral, 54 electrons arranged in the configuration [Kr] 4d10 5s2 5p6. Its standard atomic weight of 131.29 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Xenon was discovered in 1898 by William Ramsay, Morris Travers. It follows Iodine (I) and precedes Caesium (Cs) in order of atomic number.
| Atomic number | 54 |
|---|---|
| Symbol | Xe |
| Atomic mass | 131.29 |
| Category | Noble gas |
| Group | 18 |
| Period | 5 |
| Electron configuration | [Kr] 4d10 5s2 5p6 |
| Phase at STP | Gas |
| Discovered | 1898 (William Ramsay, Morris Travers) |