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Actinium is a chemical element; it has symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name emanium; the element got its name by being wrongly identified with a substance André-Louis Debierne found in 1899 and called actinium.
André-Louis Debierne had previously (in 1899 and 1900) reported the discovery of a new element actinium that was supposedly similar to titanium and thorium, which cannot have included much actual element 89. But by 1904, when Giesel and Debierne met, both had radiochemically pure element 89, and so Debierne has generally been given credit for ...
[42] [43] This was the first evidence for isotopes of a stable element; Frederick Soddy had previously proposed the existence of isotopes to explain the decay of certain radioactive elements. Thomson's separation of neon isotopes by their mass was the first example of mass spectrometry , which was subsequently improved and developed into a ...
So, element 105 was named dubnium, and element 106 was named seaborgium. The elements were placed in the periodic table’s seventh row, which is above the row of lanthanides and the row of actinides.
The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus. Rutherford directed the Geiger–Marsden experiment in 1909, which showed much more alpha particle recoil than J. J. Thomson's plum pudding model of the atom could explain. Thomson's model had ...
89 Sr is an artificial radioisotope used in the treatment of osseous (bony) metastases of bone cancer. [8] [9] In circumstances where cancer patients have widespread and painful bony metastases, the administration of 89 Sr results in the delivery of beta particles directly to the area of bony problem, where calcium turnover is greatest. [10]
This is an accepted version of this page This is the latest accepted revision, reviewed on 17 November 2024. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and ...
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