What does radioactive mean???
It means particles are periodically emitted from unstable nuclei, these particles can cause photograph negatives to expose.
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Wiki Radioactivity
A radioactive element one whose nucleus decomposes spontaneously by emitting alpha rays (helium nucleus), beta rays (electrons), or gamma rays (electromagnetic radiation). The element changes into another element if alpha or beta rays are emitted. There are other more esoteric transformations but this will cover the ground floor.
"Radioactive" refers to the property of certain atomic nuclei to decay spontaneously, emitting radiation in the process. This radiation can consist of particles (such as alpha or beta particles) or electromagnetic waves (such as gamma rays). Radioactive substances are unstable and undergo radioactive decay, which can result in the transformation of one element into another.
If you want to learn more about the concept of radioactivity, you can start by researching the work of Marie and Pierre Curie, who made significant contributions to its discovery and understanding. Additionally, studying the structure of the atom and the different types of radiation emitted during radioactive decay will deepen your understanding of the topic.