Fr
Francium (Atomic Number 87)
Category: alkali | Period 7, Group 1 | Block: s
Extremely unstable alkali metal; second-rarest element in crust.
Atomic & Physical Constants
- Standard Atomic Weight:
- 223 u
- Standard State Phase:
- Solid
- Electron Configuration:
- 2, 8, 18, 32, 18, 8, 1
- Electronegativity (Pauling):
- 0.79
- Melting Point:
- 300 K
- Boiling Point:
- 950 K
Historical Discovery & Real-World Applications
Industrial & Scientific Uses
Subatomic laser trapping spectroscopic research
Discovery History
Discovered by Marguerite Perey (1939).
Study Francium with Socratic AI Tutor
Get step-by-step orbital hybridization, oxidation state derivations, and reaction practice questions.