87 predicted 2 · 8 · 18 · 32 · 18 · 8 · 1

Francium, Fr, element 87

Alkali metal· Period 7· Group 1· s-block

Configuration [Rn]7s1

Atomic weight
223Da
Phase
solid
Density
2.458g/cm³, predicted
Melting point
294.15K 21 °C
Boiling point
No data
Electronegativity
0.7

Radioactive element, belongs to group 1 of the periodic table. Found in uranium and thorium ores. The 22 known isotopes are all radioactive, with the most stable being Fr-223. Its existence was confirmed in 1939 by Marguerite Perey. Description from mendeleev.

Back to the table
The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

4 of 5 fields have a value for francium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
223Da
Source: mendeleev
Electron configuration
[Rn]7s1
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p67s1
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 32 · 18 · 8 · 1
Source: Worked outfrom electron configuration

No data uncertainty of the atomic weight.