noun🔗ShareActinideAny of the 14 radioactive elements of the periodic table that are positioned under the lanthanides, to which they have similar chemistry."My chemistry textbook explains that the actinides are a series of radioactive elements, including uranium and plutonium, located below the lanthanides on the periodic table. "Mein Chemiebuch erklärt, dass die Actinoide eine Reihe radioaktiver Elemente sind, darunter Uran und Plutonium, die sich unter den Lanthanoiden im Periodensystem befinden.elementchemistryscienceChat with AIVocabulary GamePractice Reading