Atomic number 87
Francium
Alkali metal
Quick facts
- Atomic mass
- 223.00
- Group
- 1
- Period
- 7
- State (STP)
- solid
- Electronegativity
- 0.70
- Common ox. states
- +1
Properties
Electron configuration
[Rn] 7s¹
- Ionization energy
- 380.0 kJ/mol
- Electron affinity
- 46.9 kJ/mol
- Melting point
- 300.00 K (26.9 °C)
- Boiling point
- 950.00 K (676.9 °C)
How it bonds
Francium is the second-rarest naturally occurring element (after astatine). Predicted to be even more reactive than cesium, but every isotope decays so fast (Fr-223 has a 22-minute half-life) that no one has ever seen more than a few thousand atoms at a time.