The term radioactive is used to describe?

material that is explosive and is used in bombs
any material that causes cancer
an unstable nucleus of an atom, which means that it will spontaneously emit small amounts of radiation
the material used in a nuclear reactor

an unstable nucleus of an atom, which means that it will spontaneously emit small amounts of radiation

The term radioactive is used to describe an unstable nucleus of an atom, which means that it will spontaneously emit small amounts of radiation.

The term "radioactive" is used to describe an unstable nucleus of an atom, which means that it will spontaneously emit small amounts of radiation. This can include certain isotopes of elements like uranium, plutonium, and radium, among others. When these unstable nuclei decay, they release radiation in the form of particles and/or electromagnetic waves. This radiation can be harmful to living organisms, as it can damage cells and DNA. However, it is important to note that not all radioactive materials are used in bombs or reactors, and not all of them cause cancer. Some radioactive materials, such as those used in nuclear reactors, can be beneficial for generating electricity or treating certain medical conditions.