How the character is built
The 气 radical marks this as a gas, and that is not a coincidence of this one character — it holds right across the table. Read the radical first and the element's state at room temperature is already settled.
Written 气 over 山 — the phonetic is 仙 xiān 'immortal', abbreviated to just its 山 half.
Where you actually meet it
氙气灯 (xiānqìdēng) xenon headlamp
The element itself
Xenon makes up about ninety parts per billion of the air by volume, the rarest of the noble gases in it, and every gram is separated from liquefied air at enormous energetic cost. It is heavy enough that it is not really inert: xenon compounds exist, which came as a genuine shock when the first was made in 1962 and overturned the textbook claim that the noble gases combined with nothing. Because it is dense and easily ionised, it makes an excellent propellant for the ion engines that push spacecraft slowly and very efficiently.
Where it sits among the 118
First isolated in 1898.
The full entry
For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.
氙Xenon in the dictionary →Others built the same way
Every one of these carries 气, and every one is a gas.