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francium
[ fran-see-uhm ]
noun
, Chemistry.
- a radioactive element of the alkali metal group. : Fr; : 87.
francium
/ ˈfrænsɪəm /
noun
- an unstable radioactive element of the alkali-metal group, occurring in minute amounts in uranium ores. Symbol: Fr; atomic no: 87; half-life of most stable isotope, 223Fr: 22 minutes; valency: 1; melting pt: 27°C; boiling pt: 677°C
francium
/ frăn′sē-əm /
- 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
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Word History and Origins
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Word History and Origins
Origin of francium1
C20: from New Latin, from France + -ium ; so-called because first found in France
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Example Sentences
The last of the original 92 elements to be discovered was element 87, francium.
From Project Gutenberg
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