Edelgassene

Edelgassene, in German often written as Edelgase, are the noble gases, a group of elements in Group 18 of the periodic table. They are characterized by chemical inertness, colorless and odorless properties, and a monatomic state under standard conditions. The term Edelgassene is mainly used in German-language texts; Edelgase is the standard plural, while Edelgassene may appear as a historical or alternative form.

The noble gases are:

- Helium

- Neon

- Argon

- Krypton

- Xenon

- Radon

- Oganesson

These elements share several common features. They have full outer electron shells, which makes them highly unreactive. They have very low boiling points and typically exist as gases at room temperature. Their physical properties tend to become more extreme down the group, with heavier members generally having higher densities.

Occurrence and production: in Earth’s atmosphere they occur only in trace amounts. Helium is often found in natural gas fields and is recovered by gas separation processes, while argon, neon, krypton, and xenon are obtained from air or natural gas through cryogenic distillation and chemical processing. Radon is a radioactive decay product of uranium and thorium in the crust and is usually encountered as a health hazard in enclosed spaces.

Applications: neon lights use neon; argon serves as a shielding gas in welding; krypton and xenon are used in lighting and optics; xenon is used in anesthesia and some medical imaging; helium is essential for cryogenics, deep-sea diving gas mixes, and balloons. Oganesson is synthetic and extremely short-lived, with no practical applications to date.

History and naming: the group was identified in the late 19th to early 20th century by researchers such as Ramsay and Rayleigh. The term noble gas reflects their low chemical reactivity.