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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 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.
The nonmetals are divided into four classes that complement a four-fold division of the metals, with the noble metals treated as a subset of the transition metals. The metalloids are treated as chemically weak nonmetals, in a manner analogous to their chemically weak frontier metal counterparts. [8]
Some periodic tables distinguish elements that are metalloids and display no formal dividing line between metals and nonmetals. Metalloids are instead shown as occurring in a diagonal band [82] or diffuse region. [83] The key consideration is to explain the context for the taxonomy in use.
This line has been called the amphoteric line, [2] the metal-nonmetal line, [3] the metalloid line, [4] [5] the semimetal line, [6] or the staircase. [2] [n 1] While it has also been called the Zintl border [8] or the Zintl line [9] [10] these terms instead refer to a vertical line sometimes drawn between groups 13 and 14.
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.
Nonmetals show more variability in their properties than do metals. [1] Metalloids are included here since they behave predominately as chemically weak nonmetals.. Physically, they nearly all exist as diatomic or monatomic gases, or polyatomic solids having more substantial (open-packed) forms and relatively small atomic radii, unlike metals, which are nearly all solid and close-packed, and ...
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 post-transition metals are located on the periodic table between the transition metals to their left and the chemically weak nonmetallic metalloids or nonmetals to their right. Generally included in this category are: the group 13–16 metals in periods 4–6 namely gallium , indium and thallium , tin and lead , bismuth , and polonium ; and ...