All practice pages/Interatomic theory/Elements
Element 87, an alkali metal
The last element discovered in nature, so short-lived that only about an ounce of it exists on Earth at any moment.
Period 7, group 1. The other alkali metals are tinted, and every cell opens its own article.
One valence electron, which francium gives up easily to form the Fr⁺ ion. Like the other alkali metals, it reacts with water.
Formed in tiny amounts in uranium and thorium ores as actinium decays. Only about 20 to 30 grams are thought to exist in Earth's crust at any moment.
Marguerite Perey, a former assistant of Marie Curie, found it in 1939 at the Curie Institute in Paris while purifying actinium, and named it after France. In 1962 she became the first woman elected to the French Academy of Sciences, as a corresponding member.
None outside research. Physicists trap clouds of a few hundred thousand francium atoms with lasers to test theories of atomic structure.
Intensely radioactive; it is only ever handled a few atoms at a time.