francium
n 1: a radioactive element of the alkali-metal group discovered
as a disintegration product of actinium [syn: {francium},
{Fr}, {atomic number 87}]
francium
Symbol: Fr
Atomic number: 87
Atomic weight: (223)
Radioactive element, belongs to group 1 of the periodic table. Found in
uranium and thorium ores. The 22 known isotopes are all radioactive,
with
the most stable being Fr-223. Its existence was confirmed in 1939 by
Marguerite Perey.