Francium
Francium (钫, symbol Fr) is chemical element number 87, an Alkali Metal in period 7, group 1 of the periodic table, with a standard atomic weight of about 223. Highly radioactive alkali metal. Second rarest naturally occurring element.
Properties
| Atomic number | 87 |
|---|---|
| Symbol | Fr |
| Atomic mass | 223 u |
| Category | Alkali Metal |
| Period | 7 |
| Group | 1 |
| Electron configuration | [Rn] 7s¹ |
| Electronegativity | 0.7 |
| Covalent radius | 260 pm |
| Density | 1.87 g/cm³ |
| Melting point | 300 K |
| Boiling point | 950 K |
| Discovery | Marguerite Perey, 1939 |
Overview
Highly radioactive alkali metal. Second rarest naturally occurring element. Francium (Fr) holds position 87 in the periodic table, an Alkali Metal in period 7, group 1. As an alkali metal it is soft and highly reactive, releasing hydrogen on contact with water, and is usually stored away from air and moisture.
It has the configuration [Rn] 7s¹ and an electronegativity near 0.7; its 1 outer-shell electron drives its bonding. Under standard conditions it exists as a solid (a very low melting point); it melts near 300 K (26.9 °C), boils near 950 K (676.9 °C), has a density around 1.87 g/cm³.
It is widely used in Research. On the safety side, it carries a high hazard rating. It was first described by Marguerite Perey in 1939. See more trends in the visualization center.
Electron shells
Electrons per shell: 2 · 8 · 18 · 32 · 18 · 8 · 1
Main uses
- Research
Hazard
Compounds containing Francium
No compounds in this knowledge base contain Francium yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.