Meaning of FRANCIUM in English


Name: francium

Symbol: Fr

Atomic number: 87

Atomic weight: [ 223 ]

Group in periodic table: 1

Group name: Alkaline metal

Period in periodic table: 7

Block in periodic table: s-block

CAS registry ID: 7440-73-5

Francium occurs as a result of a disintegration of actinium. Francium is found in uranium minerals, and can be made artificially by bombarding thorium with protons. It is the most unstable of the first 101 elements. The longest lived isotope, 223Fr, a daughter of 227Ac, has a half-life of 22 minutes. This is the only isotope of francium occurring in nature, but at most there is only 20-30 g of the element present in the earth's crust at any one time. No weighable quantity of the element has been prepared or isolated. There are about 20 known isotopes.

Chemistry of the elements English vocabulary.      Английский словарь химии элементов.