There is not one, but many radioactive elements. Radioactive isotopes, to be more precise - because sometimes, one isotope may be stable, while another isotope of the same element is radioactive. All, or most, elements have radioactive isotopes.
radioactive decay
Elements that emit atomic particles are typically referred to as radioactive elements. These elements undergo radioactive decay and emit particles such as alpha particles, beta particles, or gamma rays as they try to become more stable.
Radioactive elements make up a small fraction of all naturally occurring elements in Earth's crust. Most elements are stable and non-radioactive. However, even though they are a minority, radioactive elements play important roles in various scientific, medical, and industrial applications.
Sounds to me like radiation from a radioactive isotope. The breaking down part would be the half-life. But the isotope won't completely break down. Only until it reaches a stable form. Such as, radium-226 decays finally to lead-206. During the process it emits charged Alpha particles.
Elements that decay (give off protons and neutrons) to form other elements. *It's not elements as such that are stable or unstable, but rather isotopes. Even elements of small atomic number have unstable isotopes that undergo radioactive decay, for example carbon-14. Elements with higher atomic numbers than Lead (82) are naturally radioactive in all isotopes. Bismuth (83) has an extremely long half-life, but the time generally becomes shorter (the decay more rapid) as the size of the nucleus gets progressively larger for heavier radioactive elements.
Elements with no stable isotopes are called radioactive elements. These elements spontaneously undergo radioactive decay, which leads to the formation of stable isotopes over time.
radioactive decay
The family of radioactive elements is called the Actinides. This group includes elements such as uranium, thorium, and plutonium, which are known for their radioactive properties.
This family is called, after IUPAC nomenclature -- actinoids.
Elements that emit atomic particles are typically referred to as radioactive elements. These elements undergo radioactive decay and emit particles such as alpha particles, beta particles, or gamma rays as they try to become more stable.
The elements described are said to be radioactive.
Unstable elements that decay or break down into different elements are called radioactive elements. These elements have an unstable atomic nucleus that undergoes radioactive decay, transforming into a different element and releasing energy in the process. Examples of radioactive elements include uranium, radium, and plutonium.
it was found in 1896. you can not find them on the periodic table. you may find some, but often some are.
The Actinides.
These are the alkali metals; the radioactive one is francium (Fr).
The elements with atomic numbers from 90 to 103 are called actinides. These elements are known for being radioactive and having partially filled 5f orbital. They include well-known elements like uranium, plutonium, and americium.
This phenomenon is called radioactive disintegration.