مصادر الكيمياء موقع لتعليم الكيمياء بصورة مبسطة
A chemical element, Ac, atomic number 89, and atomic weight 227.0. Actinium was discovered by A. Debierne in 1899. Milligram quantities of the element are available by irradiation of radium in a nuclear reactor. Actinium-227 is a betaemitting element whose half-life is 22 years. Six other radioisotopes with half-lives ranging …
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