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Немета́ллы — химические элементы, как правило, не обладающие свойствами металлов. Занимают правый верхний угол Периодической системы элементов Менделеева и обычно отделены линией (лесенкой). Количество неметаллов составляет 22-23 элемента, в зависимости от классификации.
Apr 28, 2024 · A nonmetal is a chemical element that mostly lacks metallic attributes. Physically, nonmetals tend to be highly volatile (easily vaporized), have low elasticity, and are good insulators of heat and …
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The chemical elements can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties. All metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metals; and have at least one basic oxide.
Nonmetals are chemical elements that mostly lack distinctive metallic properties. They range from colorless gases like hydrogen to shiny crystals like iodine. Physically, they are usually lighter (less dense) than metals; brittle or crumbly if solid; and often poor conductors of heat and electricity.
There are five general aspects of the oxidation-reduction chemistry: Nonmetals oxidize most metals. The oxidation state of the metal becomes positive as it undergoes oxidation and that of the nonmetal becomes negative as it undergoes reduction. For example: 4Fe(s)+ 0 3O2(g) 0 2Fe2O3(s) +3 −2.
Nonmetals. Elements that tend to gain electrons to form anions during chemical reactions are called non-metals. These are electronegative elements. They are non-lustrous, brittle and poor conductors of heat and electricity (except graphite). Non-metals can be gaseous, liquids or solids.
Arsenic is a semimetal, with an electrical conductivity of around 3.9 × 10 4 S•cm −1 and a band overlap of 0.5 eV. It has a moderate ionisation energy (947 kJ/mol), moderate electron affinity (79 kJ/mol), and moderate electronegativity (2.18). Arsenic is a poor oxidising agent (As + 3e → AsH 3 = –0.22 at pH 0).
