Uranium.
What an interesting question. The answer is however complex.It is possible to make small amounts of some radioactive elements or radioactive isotopes of some elements in a laboratory (usually involving a nuclear pile or an accelerator). For instance the element Plutonium is made this way.(Other radioactive elements are produced naturally by the radioactive decay of heavier radioactive elements)However, making a radioactive element or isotope from scratch requires the application of an enormous amount of energy. The place where all elements heavier than the element Iron (Fe - Atomic number 26) are made is in stellar explosions, the death of stars 8 or more times more massive than our Sun, called "supernovas".It is in supernova explosions that the radioactive elements are made.
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Radium and polonium are radioactive natural chemical elements.
No. The Curies did not discover uranium. They discovered polonium and radium, of which polonium is more radioactive.
radiometric
After disintegration all radioactive elements are transformed in other elements.
Not all of the transition elements are radioactive. Many of them are, and some of them have common radioactive isotopes, but some of them have no naturally occurring radioactive isotopes. Please note that all elements have synthetic radioactive isotopes, at least.
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.
Radioactive elements exist in all groups of the periodic table.
All elements comprising the period 7 in the periodic table are radioactive. In total this period has 32 elements.
Usually not, but all elements have radioactive isotopes.
None - they are all radioactive.
Radioactive elements exist in all groups of the periodic table.
Radioactive
All elements after 83 on the periodic table are radioactive and have unstable nuclei. They typically undergo radioactive decay to reach a more stable configuration. These elements are known as the actinides and transactinides.
all elements after uranium (atomic number 92) are radioactive.
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.