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  2. List of fictional elements, materials, isotopes and subatomic ...

    en.wikipedia.org/wiki/List_of_fictional_elements...

    The most commonly found form derives from 40 K, giving quantium-40. The name was coined by David Strauss in response to a request from the show's creator. [99] 40 K is a natural isotope, used to date rocks. But the method of getting quantium as described has not been shown in real life. 61 Pm Promethium: DC Comics

  3. Potassium-40 - Wikipedia

    en.wikipedia.org/wiki/Potassium-40

    Potassium-40 (40 K) is a radioactive isotope of potassium which has a long half-life of 1.25 billion years. It makes up about 0.012% (120 ppm ) of the total amount of potassium found in nature. Potassium-40 undergoes three types of radioactive decay .

  4. Isotopes of potassium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_potassium

    19 K) has 25 known isotopes from 34 K to 57 K as well as 31 K, as well as an unconfirmed report of 59 K. [3] Three of those isotopes occur naturally: the two stable forms 39 K (93.3%) and 41 K (6.7%), and a very long-lived radioisotope 40 K (0.012%) Naturally occurring radioactive 40 K decays with a half-life of 1.248×10 9 years. 89% of those ...

  5. 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.

  6. Isotopic labeling - Wikipedia

    en.wikipedia.org/wiki/Isotopic_labeling

    The compounds produced using stable isotopes are either specified by the percentage of labeled isotopes (that is, 30% uniformly labeled 13 C glucose contains a mixture that is 30% labeled with 13 carbon isotope and 70% naturally labeled carbon) or by the specifically labeled carbon positions on the compound (that is, 1-13 C glucose which is ...

  7. K–Ca dating - Wikipedia

    en.wikipedia.org/wiki/K–Ca_dating

    Potassium has three naturally occurring isotopes: stable 39 K, 41 K and radioactive 40 K. 40 K exhibits dual decay: through β-decay (E = 1.33 MeV), 89% of 40 K decays to 40 Ca, and the rest decays to 40 Ar via electron capture (E = 1.46 MeV). [1] While 40 K comprises only 0.001167% of total potassium mass, 40 Ca makes up 96.9821% of total ...

  8. Potassium - Wikipedia

    en.wikipedia.org/wiki/Potassium

    40 K is the radioisotope with the largest abundance in the human body. In healthy animals and people, 40 K represents the largest source of radioactivity, greater even than 14 C. In a human body of 70 kg, about 4,400 nuclei of 40 K decay per second. [33] The activity of natural potassium is 31 Bq/g. [34]

  9. K–Ar dating - Wikipedia

    en.wikipedia.org/wiki/K–Ar_dating

    t 1/2 is the half-life of 40 K; K f is the amount of 40 K remaining in the sample; Ar f is the amount of 40 Ar found in the sample. The scale factor 0.109 corrects for the unmeasured fraction of 40 K which decayed into 40 Ca; the sum of the measured 40 K and the scaled amount of 40 Ar gives the amount of 40 K which was present at the beginning ...