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nouna radioactive element of the alkali-metal group discovered as a disintegration product of actinium
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Definition that contains francium
- alkali metal any of the monovalent metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium)
- alkaline metal any of the monovalent metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium)