Francium (Fr) – element 87
Francium is a chemical element with the symbol Fr and atomic number 87. It is a alkali metal in group 1 (alkali metals), period 7 of the periodic table (s-block), and is a solid at room temperature.
Francium (Fr) has atomic number 87, atomic mass [223] and electron configuration [Rn] 7s1.
Francium facts
| Symbol | Fr |
|---|---|
| Atomic number | 87 |
| Atomic mass | [223] |
| Category | alkali metal |
| Group | group 1 (alkali metals) |
| Period | 7 |
| Block | s-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s1 |
| Noble-gas notation | [Rn] 7s1 |
| Electrons per shell | 2, 8, 18, 32, 18, 8, 1 |
| Valence electrons | 1 |
Bohr model and shells
Francium has 87 electrons in 7 shells: 2, 8, 18, 32, 18, 8, 1. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 300 K (26.9 °C) |
|---|---|
| Boiling point | 950 K (676.9 °C) |
| Density | 1.87 g/cm³ |
| Electronegativity (Pauling) | 0.79 |
| Electron affinity | 46.89 kJ/mol |
| Ionization energies | 380 kJ/mol (1st) |
| Discovered by | Marguerite Perey |
Use the atomic mass in the molar mass calculator for any formula containing Fr.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of francium?
The atomic mass of francium is [223] (mass number of its longest-lived isotope, since it has no stable isotope).
What is the electron configuration of francium?
Francium has 87 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s¹, or [Rn] 7s¹ in noble-gas notation. Electrons per shell: 2, 8, 18, 32, 18, 8, 1.
How many valence electrons does francium have?
Francium has 1 valence electron (group 1).
Is francium a metal?
Yes. Francium is a alkali metal.
Where is francium on the periodic table?
Francium is in group 1 (alkali metals), period 7, in the s-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.