- Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). Francium’s isotopes decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s1; thus, the element is classed as an alkali metal.
- Parallel Lives (Wikipedia)
The Parallel Lives (Greek: Βίοι Παράλληλοι, Bíoi Parállēloi; Latin: Vītae Parallēlae) is a series of 48 biographies of famous men written by the Greco-Roman philosopher, historian, and Apollonian priest Plutarch, probably at the beginning of the second century…