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  Protactinium

Sigma KEE - Protactinium

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protactinium
Radioactive metallic element, belongs to the actinoids. The most stable isotope, Pa-231 has a half-life of 2.43*10^4 years. At least 10 other radioactive isotopes are known. No practical applications are known. Discovered in 1917 by Lise Meitner and Otto Hahn.
Relationships      
Parents elemental substance 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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