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Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 Sr undergoes β − decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...
The longest-lived of these isotopes, and the most relevantly studied, are 90 Sr with a half-life of 28.9 years, 85 Sr with a half-life of 64.853 days, and 89 Sr (89 Sr) with a half-life of 50.57 days. All other strontium isotopes have half-lives shorter than 50 days, most under 100 minutes.
isotope half-life 10 −21 seconds fluorine-15: 1.11 oxygen-12: 1.14 sodium-18: 1.34 lithium-10m2: 1.35 helium-10: 1.52 lithium-10: 2 carbon-8: 2 beryllium-13: 2.7 helium-7: 2.51 lithium-13: 3.3 lithium-10m1: 3.7 neon-16: 3.74 beryllium-6: 5 helium-9: 7 fluorine-16: 11 boron-9: 845
Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical ...
Though 90 Y has a short half-life, it exists in secular equilibrium with its long-lived parent isotope, strontium-90 (90 Sr) (half-life 29 years). [14] All group 3 elements have an odd atomic number, and therefore few stable isotopes. [10]
Environmental radioactivity is part of the overall background radiation and is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 ( 90 Sr) and technetium-99 ( 99 Tc), are only found on Earth as a result of human activity, and some, like potassium-40 ( 40 K), are only present due to natural ...
to be 1.9 × 10 19 years. [2] [3] Technetium and promethium (atomic numbers 43 and 61, respectively [a]) and all the elements with an atomic number over 82 only have isotopes that are known to decompose through radioactive decay. No undiscovered elements are expected to be stable; therefore, lead is considered the heaviest stable element.
The survey could not show at the time, nor in the decades that have elapsed, that the levels of global strontium-90 or fallout in general, were life-threatening, primarily because "50 times the strontium-90 from before nuclear testing" is a minuscule number, and multiplication of minuscule numbers results in only a slightly larger minuscule number.