Francium (Fr)
"Meet Francium, the Phantom Atom! This super-rare, ultra-radioactive alkali metal is so fleeting and powerful, it vanishes in a flash, leaving behind a wake of pure energy!"
A memorable persona to anchor Fr in your mind.
1.87
Grams per cm³
21
Celsius (°C)
348
Radius (pm)
Daily Life Link
Imagine a sparkler that burns out almost instantly – that's how fleeting Francium's presence is in the natural world!
Discovery & History
Year Discovered
1939
Discovered By
Marguerite Perey
Origin of Name
"Francium is named after France."
Technical Properties
Atomic Mass
[223] u
Standard State
solid
Boiling Point
650°C
Electron Configuration
[Rn] 7s1
1st Ionization Energy
3.9 eV
Electron Affinity
N/A
Oxidation States
"A shimmering, silvery-white liquid metal, if you could ever catch a glimpse before it explosively reacts."
Did You Know?
Rarest of the Rare: Francium is the second-rarest naturally occurring element on Earth, behind Astatine. If you gathered all the Francium present on Earth at any given moment, you'd have less than a few ounces!
Born from Decay: You don't 'mine' Francium; it's a transient product formed when Actinium-227 undergoes alpha decay. It literally appears and disappears!
Queen of Reactivity: As the heaviest alkali metal, Francium is considered the most electropositive and potentially the most reactive element in the entire periodic table, ready to explode on contact with water!
Fleeting Existence: Its longest-lived isotope, Francium-223, has a half-life of only 22 minutes! Most other isotopes last mere seconds or milliseconds. Talk about a short shelf life!