Element 87
Francium
Alkali metals
Francium (Fr) is in the s-block of the periodic table — group 1, period 7.
Francium is a chemical element with symbol Fr and atomic number 87.
Key data
- Atomic number
- 87
- Atomic mass
- 223.000 u
- Group / Period
- 1 / 7
- Block
- s-block
- Phase at STP
- Solid
- Density
- 1.87 g/cm³
- Melting point
- 26.9 °C
- Boiling point
- 676.9 °C
- Electron configuration
- [Rn] 7s1
Periodic table block
Francium is in the s-block (group 1, period 7). Elements land in the s-block when their highest-energy electrons fill an s subshell — this includes hydrogen, helium, and the reactive metals on the far left of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Research only
- •Extremely rare
- •Heaviest alkali metal
Discovery
Year: 1939
Discovered by: Marguerite Perey
Frequently asked questions
What is the atomic number of Francium?
Francium has atomic number 87. Its symbol is Fr and its atomic mass is 223 u.
What category of element is Francium?
Francium is classified as alkali metals. It sits in group 1, period 7 of the periodic table.
What block of the periodic table is Francium in?
Francium is in the s-block (group 1, period 7). Its highest-energy electrons occupy the s subshell — you can see this in its electron configuration, [Rn] 7s1.
What is Francium used for?
Common uses of Francium include: Research only, Extremely rare, Heaviest alkali metal.
When was Francium discovered?
Francium was discovered in 1939 by Marguerite Perey.
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