087Alkali metal · Group 1 · Period 7
Francium
Francium (Fr) is element 87, a alkali metal in the s-block — group 1, period 7. It is a solid at room temperature with 7 electron shells (2, 8, 18, 32, 18, 8, 1) and an atomic mass of 223 u.
- Atomic mass
- 223.0 u
- Phase · STP
- solid
- Melting
- 300 K · 27 °C
- Boiling
- 950 K · 677 °C
- Electronegativity
- 0.79
- Density
- 1.87 g/cm³
Photograph — Chemical ELements A Virtual Museum, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0> source: https://images-of-elements.com/francium.jpg
Identity
- Atomic number
- 87
- Standard atomic weight
- 223.0 u
- Category
- Alkali metal
- Group
- 1 · Alkali metals
- Period
- 7
- Block
- s-block
- Oxidation states
- +1
Physical properties
- Melting point
- 300 K · 27 °C
- Boiling point
- 950 K · 677 °C
- Density
- 1.87 g/cm³
- Molar heat capacity
- —
- Atomic radius
- 348 pm
- Electron affinity
- 46.89 kJ/mol
Atomic structure
87protons
136neutrons
87electrons
1valence e⁻
- Noble-gas notation
- [Rn] 7s1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s1
- Electrons per shell
- 2, 8, 18, 32, 18, 8, 1
Periodic trends
Where Francium ranks across all 118 elements.
Discovery
- Discovered
- 1939
- Discovered by
- Marguerite Perey
- Named by
- —
- Appearance
- —