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Pu 239 can be put in highly toxic radioactive isotopes. As you know radio isotopes are mostly generated from the radioactive decay reactions and the heaviest material naturally occurring is U238. Pu239 is mostly created in artificial nuclear reactions. The danger of the radio isotopes is measured by their half lives. Radio isotopes having longer half ...


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According to https://en.wikipedia.org/wiki/Synthetic_element , all stable isotopes created artificially can also be found in nature (I don't have a more reliable source). EDIT(06/07/2016): see also the table of natural abundance of stable nuclides at https://www.ncsu.edu/chemistry/msf/pdf/IsotopicMass_NaturalAbundance.pdf (if an element does not have stable ...


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It's possible to imagine living in a different universe where most nuclei of the element with charge 1 were deuterium, and the lighter protium was the rare outlier. However, we don't live in that universe. Most of the ordinary matter in the universe is hydrogen (75% by mass) and helium (25% by mass) which has been unprocessed since the Big Bang. Deuterium ...


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There's a type of alloy called interstitial alloy, which might increase the density of the metal, while perhaps not expanding its volume, by introducing small atoms that can fit


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Copper is quite a dense metal at 8.96. Both the stable copper oxides are lower density. I do not believe any surface treatment could increase the bulk density of pure copper, unless there are cavities in the material. The only way apparent density might increase is if the volume is assumed constant and the treatment causes the surface to adsorb external ...



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