ACTINIUM

Actinium

Actinium is a radioactive chemical element with symbol Ac and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium and lawrencium in the periodic table.

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actinium

Noun

  1. a radioactive, metallic chemical element (symbol: Ac) with an atomic number of 89; found in uranium ores


The above text is a snippet from Wiktionary: actinium
and as such is available under the Creative Commons Attribution/Share-Alike License.

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