Here are the matches for each element with its correct group:
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Cerium (Ce) __________: Lanthanoids (Lanthanide Series)
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Astatine (At) __________: Halogens
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Radon (Rn) __________: Noble Gases
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Magnesium (Mg) __________: Alkaline Earth Metals
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Thorium (Th) __________: Actinoids (Actinide Series)
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Lithium (Li) __________: Alkali Metals
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Manganese (Mn) __________: Transition Metals
So, the completed matches are:
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Cerium (Ce) - Lanthanoids (Lanthanide Series)
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Astatine (At) - Halogens
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Radon (Rn) - Noble Gases
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Magnesium (Mg) - Alkaline Earth Metals
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Thorium (Th) - Actinoids (Actinide Series)
-
Lithium (Li) - Alkali Metals
-
Manganese (Mn) - Transition Metals