Ununennium

Ununennium, or element 119, is a predicted chemical element. Its symbol is Uue. Ununennium and Uue are substitute names made by the IUPAC, (meaning "one-one-nine-ium" in Latin) until permanent names are made. Ununennium is the element with the smallest atomic number that has not been created yet. Qualities of Ununennium are unknown, but many are predicted. It is predicted all isotopes will be radioactive. It is thought to be an alkali metal.

Many attempts have been made by American, German, and Russian teams to make ununennium but all have failed. Japanese and Russian teams failed to produce the element after work in both 2019 and 2020. The work of the Japanese team is ongoing, although no atoms of ununennium have ever been observed.

 Predicted chemistry 
Ununennium's spot on the periodic table is a sign that it may be similar to lighter elements such as lithium, sodium, potassium, rubidium, caesium, and francium; however, some of its properties may be different from what is expected. For example, ununennium might be less reactive than caesium and francium and will behave more like potassium or rubidium.

 Uses 
As of 2026, it has not been made and has no use.

References

Category:Alkali metals
Category:Hypothetical chemical elements