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Physically, they are usually lighter (less dense) than elements that form metals and are often poor conductors of heat and electricity. Chemically, nonmetals have relatively high electronegativity or usually attract electrons in a chemical bond with another element, and their oxides tend to be acidic.
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.
Nonmetals, including (to a limited extent) xenon and probably radon, usually exist as anions or oxyanions in aqueous solution; they generally form ionic or covalent compounds when combined with metals (unlike metals, which mostly form alloys with other metals); and have acidic oxides whereas the common oxides of nearly all metals are basic.
For instance metalloids are often used in high-temperature alloys, [29] and nonmetals in precipitation hardening in steels and other alloys. [30] Here the description implicitly includes information on whether the dopants tend to be electron acceptors that lead to covalently bonded compounds rather than metallic bonding or electron acceptors.
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 ...
Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and a positive ion. [5]
However, 2+ ions (Be 2+) or even 1+ (Li +) show some polarizing power because their sizes are so small (e.g., LiI is ionic but has some covalent bonding present). Note that this is not the ionic polarization effect that refers to the displacement of ions in the lattice due to the application of an electric field.
Like gold, which can form compounds containing the −1 auride ion, platinum can form compounds containing platinide ions, such as the Zintl phases BaPt, Ba 3 Pt 2 and Ba 2 Pt, being the first (unambiguous) transition metal to do so. [21] Darmstadtium should be similar to its lighter homologue platinum. It is expected to have a close-packed ...