Francium
Definition and meaning of Francium in chemistry.
![Francium element card: symbol Fr, atomic number 87, atomic mass [223], electron configuration [Rn] 7s¹, oxidation states +1, Alkali metal, group 1, period 7.](/assets/images/terms/francium-chemical-element.webp)
Francium is a highly radioactive and extremely reactive alkali metal with the symbol Fr and atomic number 87. It ranks as the second rarest natural element in Earth's crust. It only exists in very tiny, highly unstable amounts at any given time.
In more detail
Francium sits at the bottom of group 1 on the periodic table, right below cesium. It shows the extreme properties of an alkali metal, including a single valence electron that it loses very easily. This outer electron allows the metal to react violently with water and air.
Francium forms naturally through the radioactive decay of actinium-227 in uranium ores. However, the element is so unstable that only a few grams exist across the Earth at any time. Francium-223 is the longest-lived isotope, but it has a half-life of only 22 minutes.
Students often think scientists can store francium in oil like sodium, but its decay makes this impossible. If you gathered a visible amount of francium, the heat from its radiation would vaporize it instantly. To make francium, physicists bombard gold targets with high-speed oxygen atoms inside a particle accelerator.
Scientists predict that francium would melt near room temperature, but they cannot verify this through direct testing. Because of these extreme properties, francium has no commercial uses in industry. Scientists only create it in small batches to study the structure of heavy atoms.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Fr |
| Atomic number | 87 |
| Atomic mass | [223] u |
| Category | Alkali-Metal |
| Longest-lived isotope | Francium-223 |
Researchers capture tiny amounts of artificial francium in special magnetic and laser traps. They use these traps to study the energy levels of its electrons safely before they decay. This precise work helps scientists test complex physics theories about the behavior of heavy nuclei.
Frequently asked questions
Why is francium so highly reactive compared to other alkali metals?
Francium has a very large atomic radius and a single outer electron. This electron is far from the nucleus, so the atom loses it very easily during chemical reactions.
How do scientists study francium if it decays so quickly?
Scientists produce francium artificially inside large particle accelerators. They use magnetic fields and laser light to trap and study a few thousand atoms at a time.
Can you find francium in mineral deposits like other metals?
No, you cannot mine francium because it only forms as a temporary step during uranium decay. Any francium that forms quickly disappears due to its short half-life.
Related terms
Sources & references
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