87
Francium
Atomic Number87
Atomic Mass223 u
CategoryAlkali Metal
State at Room TempSolid
Year Discovered1939
About Francium
The most unstable of the first 101 elements: no francium atom survives longer than a few minutes. Discovered by Marguerite Perey, who named it for France and became the first woman elected to the French Academy of Sciences. A few grams of crust contain barely an atom of it at any time. Studied in laser traps, atom by atom, it mostly confirms what theory predicted about heavy alkali metals.
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