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  2. List of radioactive nuclides by half-life - Wikipedia

    en.wikipedia.org/wiki/List_of_radioactive...

    This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds. [1]

  3. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation. The accompanying table shows the ...

  4. List of elements by stability of isotopes - Wikipedia

    en.wikipedia.org/wiki/List_of_elements_by...

    This is the longest half-life directly measured for any unstable isotope; [4] only the half-life of tellurium-128 is longer. [ citation needed ] Of the chemical elements, only 1 element ( tin ) has 10 such stable isotopes, 5 have 7 stable isotopes, 7 have 6 stable isotopes, 11 have 5 stable isotopes, 9 have 4 stable isotopes, 5 have 3 stable ...

  5. List of nuclides - Wikipedia

    en.wikipedia.org/wiki/List_of_nuclides

    At least 3,300 nuclides have been experimentally characterized [1] (see List of radioactive nuclides by half-life for the nuclides with decay half-lives less than one hour). A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either is stable or has an observed decay mode .

  6. Technetium-99m - Wikipedia

    en.wikipedia.org/wiki/Technetium-99m

    This is still a short half-life relative to many other known modes of radioactive decay and it is in the middle of the range of half lives for radiopharmaceuticals used for medical imaging. After gamma emission or internal conversion, the resulting ground-state technetium-99 then decays with a half-life of 211,000 years to stable ruthenium-99 ...

  7. Livermorium - Wikipedia

    en.wikipedia.org/wiki/Livermorium

    Six isotopes of livermorium are known, with mass numbers of 288–293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 80 milliseconds. A seventh possible isotope with mass number 294 has been reported but not yet confirmed. In the periodic table, it is a p-block transactinide element.

  8. Californium - Wikipedia

    en.wikipedia.org/wiki/Californium

    This short half-life means the element is not found in significant quantities in the Earth's crust. [a] 252 Cf, with a half-life of about 2.645 years, is the most common isotope used and is produced at Oak Ridge National Laboratory (ORNL) in the United States and Research Institute of Atomic Reactors in Russia.

  9. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. [11] Radioactive. [11] protactinium: 91: 1b: Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. [11] Both toxic and highly radioactive. radium: 88: 1bc