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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.
The periodic trends in properties of elements. In chemistry, periodic trends are specific patterns present in the periodic table that illustrate different aspects of certain elements when grouped by period and/or group. They were discovered by the Russian chemist Dmitri Mendeleev in 1863.
Atomic radii vary in a predictable and explicable manner across the periodic table. For instance, the radii generally decrease rightward along each period (row) of the table, from the alkali metals to the noble gases; and increase down each group (column). The radius increases sharply between the noble gas at the end of each period and the ...
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 ...
Prior to Mendeleev's publication in 1869 of the first (eventually) widely accepted periodic table, Odling published a table in 1864, in which the "noble metals" rhodium, ruthenium, palladium; and platinum, iridium, and osmium were grouped together, [7] and adjacent to silver and gold.
Elements in the same group tend to show similar chemical characteristics. Vertical, horizontal and diagonal trends characterize the periodic table. Metallic character increases going down a group and from right to left across a period. Nonmetallic character increases going from the bottom left of the periodic table to the top right.
Renters tend to have poorer credit profiles than homeowners: in data from 2010 to 2015, 84% of renters had scores below 550, while only 27% of those with scores over 750 were renters. That makes ...