Ununennium
![Orbitals with high azimuthal quantum number are raised in energy, eliminating what would otherwise be a gap in orbital energy corresponding to a closed proton shell at element 114, as shown in the left diagram which does not take this effect into account. This raises the next proton shell to the region around element 120, as shown in the right diagram, potentially increasing the half-lives of element 119 and 120 isotopes.[24]](/uploads/202501/10/Next_proton_shell.svg1617.png)
![A chart of nuclide stability as used by the Dubna team in 2010. Characterized isotopes are shown with borders. Beyond element 118 (the last known element), the line of known nuclides is expected to rapidly enter a region of instability, with no half-lives over one microsecond after element 121. The elliptical region encloses the predicted location of the island of stability.[10]](/uploads/202501/10/Island_of_Stability_derived_from_Zagrebaev1617.png)
![Empirical (Na–Cs, Mg–Ra) and predicted (Fr–Uhp, Ubn–Uhh) atomic radii of the alkali and alkaline earth metals from the third to the ninth period, measured in angstroms[2][32]](/uploads/202501/10/Atomic_radius_of_alkali_metals_and_alkaline_earth_metals.svg1617.png)
![Empirical (Na–Cs), semi-empirical (Fr), and predicted (Uue) electron affinities of the alkali metals from the third to the eighth period, measured in electron volts.[2][32] They decrease from Li to Cs, but the Fr value, (492 ± 10) meV, is 20 meV higher than that of Cs, and that of Uue is much higher still at 662 meV.[33]](/uploads/202501/10/Electron_affinity_of_alkali_metals.svg1617.png)
Ununennium, also known as eka-francium or simply element 119, is the chemical element with atomic number 119 and symbol Uue. Ununennium and Uue are the temporary systematic IUPAC name and symbol, until a permanent name is decided upon. In the periodic table of the elements, it is expected to be an s-block element, an alkali metal, and the first element in the eighth period.