Question

All man made elements are placed after an element having atomic number 92 named_________.
(A) Beryllium
(B) Cadmium
(C) Uranium
(D) Lithium

Answer 1

The atomic number of uranium is 92. Elements having atomic numbers greater than 92 are called transuranic elements. These are man made elements synthesized by nuclear transmutation.

Complete answer:
All man made elements are transuranic elements. These are also called transuranium elements. The atomic number of transuranium elements is greater than 92. Uranium has an atomic number of 92.
The atomic numbers of beryllium, cadmium, uranium and lithium are 4, 48, 92 and 3 respectively.
Hence, all man made elements are placed after an element having atomic number 92 named Uranium.
The radioactive waste containing trans-uranium elements can be managed by artificial transmutation. During this process, nuclei having a longer half-life period are transformed into nuclei having a shorter half-life period. The nuclei are bombarded with fast moving neutrons to induce fission reactions.

Hence, the correct option is the option (C) Uranium.

Additional Information: Transuranium elements are synthesized by nuclear transformations. Naturally occurring elements are bombarded with suitable particles to induce nuclear transformations. Heavier elements are made by nuclear fusion reactions. Two small nuclei fuse to form one large nucleus. During this process, a huge amount of energy is released.

Note: During transmutation, the number of protons present in the nucleus changes. Due to change in the number of protons, the atomic number changes and another element is formed. Transmutation can be natural. It can also be artificially induced. Nuclear fusion and fission reactions are examples of nuclear transmutation processes.