Video Transcript
Uranium-238, 238 92 U, is the most common isotope of uranium. Which of the following statements best describes elements that are classified as transuranium? (A) Elements that are in the same group in the periodic table as uranium. (B) Elements that have an atomic number greater than 92. (C) All of the lanthanides and actinoids. (D) All of the elements in period seven of the periodic table. Or (E) all of the actinoids on either side of uranium.
Transuranium elements are elements past uranium in the periodic table. Uranium has an atomic number of 92, so transuranium elements are elements with an atomic number greater than 92. Transuranium elements are not usually found in nature but instead are artificially created by the process of transmutation by bombardment. In a nuclear reactor, for example, there are a large number of neutrons and uranium-238. The uranium-238 can absorb neutrons to form heavier nuclei, such as uranium-239. Then, beta decay occurs, transforming neutrons into protons to produce isotopes, such as neptunium-239 or plutonium-239. These can absorb more neutrons to form even heavier transuranium elements. Nuclear reactors can be used to produce many of the transuranium elements, but beyond californium, mostly particle accelerators are used.
So the answer to the question “Which of the following statements best describes elements that are classified as transuranium?” is (B), elements that have an atomic number greater than 92.
