Francium

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Chemical element, symbol Fr and atomic number 87

Francium

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Francium is a chemical element with the chemical symbol Fr and atomic number 87. It is an extremely rare and highly radioactive alkali metal. Francium is the second-least electronegative element, only after cesium, and is the least electron-affinitive element.

History

Francium was discovered by Marguerite Perey in 1939 while she was working as an assistant to Marie Curie at the Curie Institute in Paris. It was the last element discovered in nature rather than by synthesis. Perey named the element after her home country, France.

Characteristics

Francium is highly radioactive; its most stable isotope, francium-223, has a half-life of only 22 minutes. Due to its high instability, francium is one of the least studied elements. It is estimated that there are no more than 30 grams of francium in the Earth's crust at any given time.

Physical properties

Francium is presumed to have a melting point of around 27 °C (81 °F) and a boiling point of about 677 °C (1251 °F). It is expected to be a soft, highly reactive metal, similar to other elements in the alkali metal group.

Chemical properties

Francium reacts violently with water, producing francium hydroxide and hydrogen gas. It also reacts with halogens to form francium halides. Due to its extreme rarity and radioactivity, francium has no commercial applications and is primarily of interest for research purposes.

Isotopes

Francium has 34 known isotopes, with francium-223 being the most stable. The isotopes of francium range in atomic mass from 199 to 232. Most of these isotopes have very short half-lives, making them difficult to study.

Occurrence

Francium occurs naturally as a result of the alpha decay of actinium. It is found in trace amounts in uranium and thorium ores. Due to its short half-life, it is extremely rare in nature.

Applications

Due to its scarcity and radioactivity, francium has no significant commercial applications. It is primarily used in scientific research, particularly in the fields of nuclear physics and chemistry.

See also

• Alkali metal
• Radioactivity
• Periodic table

External links

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