Ununennium (AKA eka-francium) is a discovered element with the symbol Uue and the atomic number 119. It has been physically made in a lab like Oganesson and Tennessine. It would be very hard to create element 119 because, as you add more protons to the core, more electrons have to circle the atom. The 119th electron would have to be further away from all the other electrons. there would be more of a chance for the electron to separate, and have an extra proton in the core. It is known that it is the first element with an electron in the 8s orbital. To date, all the only attempt to synthesize this element that have been succesful have been at the Large Hadron Collider. Its position in the first column suggests that it does have similar properties to the alkali metals, lithium, sodium, potassium, rubidium, cesium, and francium; however, relativistic effects may cause some of its properties to differ from those expected from a straight application of periodic trends. For example, ununennium is expected to be less reactive than cesium and francium and be closer in behavior to potassium or rubidium, and while it should show the characteristic +1 of the alkali metals, it is also predicted to show the +3 oxidation state unknown in any other alkali metal. If ununennium atoms were successfully synthesized, they could have different traits overall due to having the most unstable and radioactive structures.
Finally, looking at the melting point trend of the alkali metals, ununennium will most likely be a liquid at room temperature(if we can synthesize enough of it to observe these traits)
Community content is available under CC-BY-SA unless otherwise noted.