87 Fr
Alkali metal
Francium
Most reactive metal.
Properties of Francium
- Atomic number (Z)
- 87
- Symbol
- Fr
- Atomic mass
- 223 g/mol
- Category
- Alkali metal
- Group
- 1
- Period
- 7
- Electron configuration
- [Rn] 7s¹
- Electronegativity (Pauling)
- 0.7
- Atomic radius
- —
- First ionization energy
- 393 kJ/mol
- Melting point
- 300 K (26.9 °C)
- Boiling point
- 950 K (676.9 °C)
- Density
- 1.87 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1939