Ununennium, also known as eka-francium or element 119, is the temporary name of a hypothetical chemical element in the periodic table that has the temporary symbol Uue and has the atomic number 119. To date, attempted syntheses of this element have been unsuccessful. Since it is below the alkali metals it might have properties similar to those of francium or caesium and thus be extremely reactive with water and air (though relativistic effects might make it less reactive than francium and caesium). A predicted oxidation state is +1; however, unlike all the other alkali metals, it is also predicted to show the +3 oxidation state.
Ununennium would be the first element in the eighth period of the periodic table.
Read more about Ununennium: Attempts At Synthesis, Predicted Decay Characteristics, Target-projectile Combinations Leading To Z=119 Compound Nuclei, Theoretical Calculations On Evaporation Cross Sections, Extrapolated Chemical Properties