The last of the original 92 elements to be discovered was element 87, francium.
francium fran·ci·um (frān'sē-əm)
n.
Symbol Fr
An extremely unstable radioactive element of the alkali metals, having [approx] 19 isotopes, the most stable of which is Fr 223 with a half-life of 21 minutes. Atomic number 87; valence 1.
| francium Symbol Fr An extremely unstable, radioactive element of the alkali group. It is the heaviest metal of the group. Francium occurs in nature, but less than 28.35 g (1 oz) is present in the Earth's crust at any time. It has approximately 19 isotopes, the most stable of which is Fr 223 with a half-life of 21 minutes. Atomic number 87; valence 1. See Periodic Table. |
