Element 100
Fermium
Actinides
Fermium (Fm) is in the f-block of the periodic table — group 3, period 7.
Fermium is a synthetic element with symbol Fm and atomic number 100.
Key data
- Atomic number
- 100
- Atomic mass
- 257.000 u
- Group / Period
- 3 / 7
- Block
- f-block
- Phase at STP
- Solid
- Density
- —
- Melting point
- 1526.8 °C
- Boiling point
- —
- Electron configuration
- [Rn] 5f12 7s2
Periodic table block
Fermium is in the f-block (group 3, period 7). Elements land in the f-block when their highest-energy electrons fill an f subshell — these are the lanthanides and actinides shown beneath the main table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Research only
- •Very short half-life
- •Synthesized post-WWII
Discovery
Year: 1953
Discovered by: Lawrence Berkeley National Laboratory
Frequently asked questions
What is the atomic number of Fermium?
Fermium has atomic number 100. Its symbol is Fm and its atomic mass is 257 u.
What category of element is Fermium?
Fermium is classified as actinides. It sits in group 3, period 7 of the periodic table.
What block of the periodic table is Fermium in?
Fermium is in the f-block (group 3, period 7). Its highest-energy electrons occupy the f subshell — you can see this in its electron configuration, [Rn] 5f12 7s2.
What is Fermium used for?
Common uses of Fermium include: Research only, Very short half-life, Synthesized post-WWII.
When was Fermium discovered?
Fermium was discovered in 1953 by Lawrence Berkeley National Laboratory.
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