Francium

87
Fr
Gruppe
1
Periode
7
Blok
s
Protons
Electrons
Neutrons
87
87
136
General Properties
Atomnummer
87
Atommasse
[223]
Mass Number
223
Kategori
Alkalimetaller
Farve
Silver
Radioactive
Ja
Francium was named after France
Krystalstruktur
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.
Elektroner i hver skal
2, 8, 18, 32, 18, 8, 1
Elektronkonfiguration
[Rn] 7s1
Fr
Francium was the last element discovered in nature, rather than by synthesis
Physical Properties
Tilstandsform
Fast stof
Massefylde
1,87 g/cm3
Smeltepunkt
296,15 K | 23 °C | 73,4 °F
Kogepunkt
950,15 K | 677 °C | 1250,6 °F
Smeltevarme
2 kJ/mol
Fordampningsvarme
65 kJ/mol
Varmefylde
-
Abundance in Earth's crust
n/a
Abundance in Universe
n/a
Illustration
Billede akkrediteringer: Images-of-elements
Illustration of francium
CAS Number
7440-73-5
PubChem CID Number
n/a
Atomic Properties
Atomradius
260 pm
Kovalent radius
348 pm
Elektronegativitet
0,7 (Paulings skala)
Ionization Potential
4,0727 eV
Atomic Volume
71,07 cm3/mol
Varmeledningsevne
0,15 W/cm·K
Oxidationstrin
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
Isotoper
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