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Rhenium is a chemical element; it has symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. It has one of the highest melting and boiling points of ...
Rhenium (Latin: Rhenus meaning: "Rhine") [56] was the last-discovered of the elements that have a stable isotope (other new elements discovered in nature since then, such as francium, are radioactive). [57] The existence of a yet-undiscovered element at this position in the periodic table had been first predicted by Dmitri Mendeleev.
Naturally occurring rhenium (75 Re) is 37.4% 185 Re, which is stable (although it is predicted to decay), and 62.6% 187 Re, which is unstable but has a very long half-life (4.12×10 10 years). [4] Among elements with a known stable isotope, only indium and tellurium similarly occur with a stable isotope in lower abundance than the long-lived ...
The darker more stable isotope region departs from the line of protons (Z) = neutrons (N), as the element number Z becomes larger. This is a list of chemical elements by the stability of their isotopes. Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable. [1] Overall, there are 251 known stable isotopes in ...
By 1939, 91 elements were known to exist, including uranium, which has 92 protons in each nucleus and, at the time, the highest atomic number in the periodic table. But element 61 was still not ...
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
The periodic table and law are now a central and indispensable part of modern chemistry. The periodic table continues to evolve with the progress of science. In nature, only elements up to atomic number 94 exist; [a] to go further, it was necessary to synthesize new elements in the laboratory.
The three elements above the platinum group in the periodic table (iron, nickel and cobalt) are all ferromagnetic; these, together with the lanthanide element gadolinium (at temperatures below 20 °C), [4] are the only known transition metals that display ferromagnetism near room temperature.