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From left to right in the periodic table, the nonmetals can be divided into the reactive nonmetals and the noble gases. The reactive nonmetals near the metalloids show some incipient metallic character, such as the metallic appearance of graphite, black phosphorus, selenium and iodine. The noble gases are almost completely inert.
The chemistry of selenium is largely covalent in nature, noting it can form ionic selenides with highly electropositive metals. The common oxide of selenium (SeO 3) is strongly acidic. Tellurium. Tellurium is a silvery-white, moderately reactive, [8] shiny solid, that has a density of 6.24 g/cm 3 and is soft (MH 2.25) and brittle. It is the ...
The most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...
Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.
Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon-to-selenium chemical bonds. [ 1 ] [ 2 ] [ 3 ] Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected.
Bettelheim et al. The nonmetals are distinguished based on the molecular structures of their most thermodynamically stable forms in ambient conditions. [5] Polyatomic nonmetals form structures or molecules in which each atom has two or three nearest neighbours (carbon: C x; phosphorus: P 4; sulfur: S 8; selenium: Se x); diatomic nonmetals form molecules in which each atom has one nearest ...
[n 6] Selenium, in particular, is commonly designated as a metalloid in environmental chemistry [n 7] on account of similarities in its aquatic chemistry with that of arsenic and antimony. [n 8] There are fewer references to beryllium, in spite of its periodic table position adjoining the dividing line between metals and nonmetals. Isolated ...
The average electronegativity for the elements in the table with densities less than 7 gm/cm 3 (metals and nonmetals) is 1.97 compared to 1.66 for the metals having densities of more than 7 gm/cm 3. There is not full agreement about the use of phenomenological properties.