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| element of group 0; element of group 0 A group of monatomic gaseous elements forming group 18 (formerly group 0) of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) | |||
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| element of group 0; element of group 0 A group of monatomic gaseous elements forming group 18 (formerly group 0) of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) | |||
