Francium

87
Fr
Group
1
Period
7
Block
s
Protons
Electrons
Neutrons
87
87
136
General Properties
Atomic Number
87
Atomic Weight
[223]
Mass Number
223
Category
Alkali metals
Color
Silver
Radioactive
Yes
Francium was named after France
Crystal Structure
n/a
History
Francium was discovered in 1939 by Marguerite Perey of the Curie Institute in Paris, France.

It was discovered when she was researching the radioactive decay of actinium-227.

Marguerite Perey discovered that francium-223 is made naturally when actinium-227 emits an alpha-particle.
Electrons per shell
2, 8, 18, 32, 18, 8, 1
Electron Configuration
[Rn] 7s1
Fr
Francium was the last element discovered in nature, rather than by synthesis
Physical Properties
Phase
Solid
Density
1.87 g/cm3
Melting Point
296.15 K | 23 °C | 73.4 °F
Boiling Point
950.15 K | 677 °C | 1250.6 °F
Heat of Fusion
2 kJ/mol
Heat of Vaporization
65 kJ/mol
Specific Heat Capacity
-
Abundance in Earth's crust
n/a
Abundance in Universe
n/a
Illustration
Image Credits: Images-of-elements
Illustration of francium
CAS Number
7440-73-5
PubChem CID Number
n/a
Atomic Properties
Atomic Radius
260 pm
Covalent Radius
348 pm
Electronegativity
0.7 (Pauling scale)
Ionization Potential
4.0727 eV
Atomic Volume
71.07 cm3/mol
Thermal Conductivity
0.15 W/cm·K
Oxidation States
1
Applications
Due to its instability and rarity, there are no commercial applications for francium.

It has been used for research purposes in the fields of biology and of atomic structure.

Its use as a potential diagnostic aid for various cancers has also been explored, but this application has been deemed impractical.
Francium is highly radioactive
Isotopes
Stable Isotopes
-
Unstable Isotopes
199Fr, 200Fr, 201Fr, 202Fr, 203Fr, 204Fr, 205Fr, 206Fr, 207Fr, 208Fr, 209Fr, 210Fr, 211Fr, 212Fr, 213Fr, 214Fr, 215Fr, 216Fr, 217Fr, 218Fr, 219Fr, 220Fr, 221Fr, 222Fr, 223Fr, 224Fr, 225Fr, 226Fr, 227Fr, 228Fr, 229Fr, 230Fr, 231Fr, 232Fr