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  2. Radioactive decay - Wikipedia

    en.wikipedia.org/wiki/Radioactive_decay

    Recent results suggest the possibility that decay rates might have a weak dependence on environmental factors. It has been suggested that measurements of decay rates of silicon-32 , manganese-54 , and radium-226 exhibit small seasonal variations (of the order of 0.1%).

  3. Curie (unit) - Wikipedia

    en.wikipedia.org/wiki/Curie_(unit)

    The activity of a sample decreases with time because of decay. The rules of radioactive decay may be used to convert activity to an actual number of atoms. They state that 1 Ci of radioactive atoms would follow the expression N (atoms) × λ (s −1) = 1 Ci = 3.7 × 10 10 Bq, and so N = 3.7 × 10 10 Bq / λ, where λ is the decay constant in s ...

  4. Radium - Wikipedia

    en.wikipedia.org/wiki/Radium

    226 Ra is the most stable isotope of radium and is the last isotope in the (4 n + 2) decay chain of uranium-238 with a half-life of over a millennium; it makes up almost all of natural radium. Its immediate decay product is the dense radioactive noble gas radon (specifically the isotope 222 Rn ), which is responsible for much of the danger of ...

  5. Radium-226 - Wikipedia

    en.wikipedia.org/wiki/Radium-226

    The decay-chain of uranium-238, which contains radium-226 as an intermediate decay product. 226 Ra occurs in the decay chain of uranium-238 (238 U), which is the most common naturally occurring isotope of uranium. It undergoes alpha decay to radon-222, which is also radioactive; the decay chain ultimately terminates at lead-206. Because of its ...

  6. Radiometric dating - Wikipedia

    en.wikipedia.org/wiki/Radiometric_dating

    The radioactive decay constant, the probability that an atom will decay per year, is the solid foundation of the common measurement of radioactivity. The accuracy and precision of the determination of an age (and a nuclide's half-life) depends on the accuracy and precision of the decay constant measurement. [ 11 ]

  7. Specific activity - Wikipedia

    en.wikipedia.org/wiki/Specific_activity

    One gram of rubidium-87 and a radioactivity count rate that, after taking solid angle effects into account, is consistent with a decay rate of 3200 decays per second corresponds to a specific activity of 3.2 × 10 6 Bq/kg. Rubidium atomic mass is 87 g/mol, so one gram is 1/87 of a mole. Plugging in the numbers:

  8. Isotopes of radium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_radium

    Radium (88 Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226 Ra with a half-life of 1600 years. 226 Ra occurs in the decay chain of 238 U (often referred to as the radium series). Radium has 34 known isotopes from 201 Ra to 234 Ra.

  9. Radium and radon in the environment - Wikipedia

    en.wikipedia.org/wiki/Radium_and_radon_in_the...

    Radium, like radon, is radioactive and is found in small quantities in nature and is hazardous to life if radiation exceeds 20-50 mSv/year. Radium is a decay product of uranium and thorium. [2] Radium may also be released into the environment by human activity: for example, in improperly discarded products painted with radioluminescent paint.