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e. Heavy metals are metallic elements with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context and has been argued should not be used. [2][3] A heavy metal may be defined on the basis of density, atomic number or chemical behaviour.
Osmium (from Ancient Greek ὀσμή (osmḗ) 'smell') is a chemical element; it has symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element. When experimentally measured using ...
Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context. [2] In metallurgy, for example, a heavy metal may be defined on the basis of density, whereas in physics the distinguishing criterion ...
Due to having the lowest atomic weight and the largest atomic radius of all the elements in their periods, the alkali metals are the least dense metals in the periodic table. [71] Lithium, sodium, and potassium are the only three metals in the periodic table that are less dense than water: [ 5 ] in fact, lithium is the least dense known solid ...
Z ≥ 104 (Rf) Superheavy elements, also known as transactinide elements, transactinides, or super-heavy elements, or superheavies for short, are the chemical elements with atomic number greater than 104 [1]. The superheavy elements are those beyond the actinides in the periodic table; the last actinide is lawrencium (atomic number 103).
In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides, separated from known stable and long-lived primordial radionuclides.
Radium is the heaviest known alkaline earth metal and is the only radioactive member of its group. Its physical and chemical properties most closely resemble its lighter congener, barium. [3] Pure radium is a volatile silvery-white metal, although its lighter congeners calcium, strontium, and barium have a slight yellow tint. [3]
A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; [a] the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.