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Sigma KEE - Francium
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Francium
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.
Relationships      
Parents ElementalSubstance The Class of PureSubstances that cannot be separated into two or more Substances by ordinary chemical (or physical) means. This excludes nuclear reactions. ElementalSubstances are composed of only one kind of atom. Examples: Iron (Fe), copper (Cu), and oxygen (O_2). ElementalSubstances are the simplest PureSubstances.


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