Francium is a chemical element with the chemical symbol Fr and an atomic number of 87. It is a metal. In chemistry it is placed in a group of metal elements named the alkali metals. Francium is very radioactive. It is in very small amounts in uranium and thorium ores. It has the lowest electronegativity and electron affinity of all the chemical elements.
Francium reacts violently with water, as do all of the elements in group 1 on the periodic table.