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Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals.
Polonium is a chemical element; it has symbol Po and atomic number 84. A rare and highly radioactive metal (although sometimes classified as a metalloid ) with no stable isotopes , polonium is a chalcogen and chemically similar to selenium and tellurium , though its metallic character resembles that of its horizontal neighbors in the periodic ...
Tellurium is a soft (MH 2.25) and brittle semi-metallic element. It is commonly regarded as a metalloid, or by some authors either as a metal or a non-metal. Tellurium has a polyatomic (CN 2) hexagonal crystalline structure. It is a semiconductor with a band gap of 0.32 to 0.38 eV.
The chemical elements can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties.All elemental metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metallic elements; and have at least one basic oxide.
Oxygen, sulfur, and selenium are nonmetals, and tellurium is a metalloid, meaning that its chemical properties are between those of a metal and those of a nonmetal. [7] It is not certain whether polonium is a metal or a metalloid. Some sources refer to polonium as a metalloid, [2] [27] although it has some metallic properties.
Periodic table of the chemical elements showing the most or more commonly named sets of elements (in periodic tables), and a traditional dividing line between metals and nonmetals. The f-block actually fits between groups 2 and 3; it is usually shown at the foot of the table to save horizontal space.
The elements commonly classified as metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. [n 4] The status of polonium and astatine is not settled. Most authors recognise one or the other, or both, as metalloids; Herman, Hoffmann and Ashcroft, on the basis of relativistic modelling, predict astatine will be a monatomic metal.
A metalloid is an element that possesses a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals, and which is therefore hard to classify as either a metal or a nonmetal. This is a generic definition that draws on metalloid attributes consistently cited in the literature.