Quick Facts
| Property | Value |
|---|---|
| Symbol | Fr |
| Atomic Number | 87 |
| Atomic Mass | [223] u |
| Category | Alkali Metal |
| Period | 7 |
| Group | 1 |
| Block | s |
| Electron Configuration | [Rn] 7s¹ |
History and Discovery
Discovered by: Marguerite Perey Year of Discovery: 1939 Location: Paris, France
Etymology
Named after France, homeland of its discoverer.
Properties
- Most unstable of all naturally occurring elements
- Longest-lived isotope has 22-minute half-life
- Never been seen in bulk
- Most electropositive element
Interesting Facts
- Predicted by Mendeleev as "eka-caesium"
- Less than 30 grams exists in Earth's crust at any time
- Would be liquid at room temperature (theoretical)
- Last element discovered in nature (1939)
- Named after France by Marguerite Perey