A large collection of radioactive atoms is called?

• A. Isotope family
• B. Radioactive Material
• C. Nuclear chain
• D. Radioactive group

Answer: (B)

Radioactive material is the term for any substance that contains radioactive atoms. When you have a large collection of radioactive atoms, you’re dealing with radioactive material because the material itself contains radionuclides that emit ionizing radiation. This label is used in safety, labeling, handling, and transportation to describe the substance as a whole, regardless of the specific amount. The other terms don’t fit because an isotope family refers to related forms of an element, not a bulk substance; a nuclear chain describes a chain reaction, not a collection of atoms; and a radioactive group isn’t a standard regulatory term. In general, more radioactive atoms mean higher activity, but the proper name for the substance is radioactive material.