At these speeds the electrons become closer to the nucleus than expected, and they are consequently harder to remove. Put simply, the size and mass of francium means that its electrons are travelling at very high speeds.
In the heaviest elements in the periodic table, relativistic effects lead to some weird behaviour. However, francium bucks this trend, due to weird effects that occur as elements get heavier.
The reactivity of the group 1 elements increases as you descend the group, with the elements’ outermost electron becoming easier to remove during reactions. You might expect that francium, sat at the foot of the group 1 elements, would be the most reactive of the bunch. Its most stable isotope has a half-life of just 22 minutes. Subsequently, Perey named the new element francium after her native France.įrancium is vanishingly rare it’s estimated that less than 30 grams of the element are present in the Earth’s crust at any given time.
However, this name was rejected by one of her supervisors, Irene Joliot-Curie (Marie Curie’s daughter). Perey original suggested the name ‘catium’ for her newly discovered element. Francium was discovered in 1939 by Marguerite Perey, who was working at the Curie Institute in Paris.
