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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.
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 ...
For example, the periodic table in the Encyclopaedia Britannica recognizes noble gases, halogens, and other nonmetals, and splits the elements commonly recognized as metalloids between "other metals" and "other nonmetals". [103] On the other hand, seven of twelve color categories on the Royal Society of Chemistry periodic table include nonmetals.
Twenty-two nonmetals including B, Si, Ge, As and Te. Tin and antimony are shown as being intermediate between metals and nonmetals; they are later shown as either metals or nonmetals. Astatine is counted as a metal. Emsley J 1971, The Inorganic Chemistry of the Non-metals, Methuen Educational, London, ISBN 978-0-423-86120-4. Twenty nonmetals.
In 1891, Walker published a periodic "tabulation" with a diagonal straight line drawn between the metals and the nonmetals. [14] In 1906, Alexander Smith published a periodic table with a zigzag line separating the nonmetals from the rest of elements, in his highly influential [15] textbook Introduction to General Inorganic Chemistry. [16]
Krypton atoms chemically bound to other nonmetals (hydrogen, chlorine, carbon) as well as some late transition metals (copper, silver, gold) have also been observed, but only either at low temperatures in noble gas matrices, or in supersonic noble gas jets. [40]
These definitions are equivalent to stating that metals conduct electricity at absolute zero, as suggested by Nevill Francis Mott, [2]: 257 and the equivalent definition at other temperatures is also commonly used as in textbooks such as Chemistry of the Non-Metals by Ralf Steudel [3] and work on metal–insulator transitions. [4] [5]