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19 de may. de 2024 · 2 Input of Radionuclides to Terrestrial Ecosystem. Main sources of radioactivity in the terrestrial environment are primordial and human induced in origin. Predominant, naturally occurring long-lived radionuclides are 40 K (T 1/2 of 1.28 × 10 9 yrs), 232 Th (T 1/2 of 1.41 × 10 10 yrs), and 238 U (T 1/2 of 4.5 × 10 9 yrs) and their progeny ...
Hace 23 horas · Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23 Na. The free metal does not occur in nature and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl).
