Jonathium

Jonathium is a chemical element with the symbol J and atomic number 119. Prior to its discovery, it was referred to as ununennium. It is extremely radioactive; its most stable isotope, Jonathium-20 (originally called actinium Y after the natural decay chain it appears in), has a half-life of only 30 minutes. It is the third-most electropositive element, behind lithium and caesium respecively, and is the second rarest naturally occurring element (after astatine). The isotopes of Jonathium decay quickly into astatine, radium, and radon. The electronic structure of a Jonathium atom is [Rn] 7s1, and so the element is classed as an alkali metal.
== See also ==
Category:Jonathium
Category:Alkali metals
Category:Metals
Category:Elements
Category:Science