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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 ...
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.
Rubidium–strontium dating. The rubidium–strontium dating method (Rb–Sr) is a radiometric dating technique, used by scientists to determine the age of rocks and minerals from their content of specific isotopes of rubidium (87 Rb) and strontium (87 Sr, 86 Sr). One of the two naturally occurring isotopes of rubidium, 87 Rb, decays to 87 Sr ...
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 ...
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 ]