![]() in the periodic table, anomalies too-some of them profound. Others count some of the metalloids as post-transition metals. Some authors count metalloids as nonmetals with weakly nonmetallic properties. Metalloids, straddling the metal-nonmetal border, are mostly distinct from either, but in a few properties resemble one or the other, as shown in the shading of the metalloid column below and summarized in the small table at the top of this section.Īuthors differ in where they divide metals from nonmetals and in whether they recognize an intermediate metalloid category. The characteristic properties of metals and nonmetals are quite distinct, as shown in the table below. ![]() Metalloids Tellurium, described by Dmitri Mendeleev as forming a transition between metals and nonmetals Specialized subcategories such as the refractory metals and the noble metals also exist. From left to right in the periodic table, these categories include the highly reactive alkali metals the less-reactive alkaline earth metals, lanthanides, and radioactive actinides the archetypal transition metals and the physically and chemically weak post-transition metals. Metals comprise the large majority of the elements, and can be subdivided into several different categories. ![]() Au, Pt), or have nonmetallic structures ( Mn and Ga are structurally analogous to, respectively, white P and I). Ti, Re), or are noble (hard to oxidise, e.g. W, Nb), are liquids at or near room temperature (e.g. Be, Al) or very high melting points (e.g. Some metals appear coloured ( Cu, Cs, Au), have low densities (e.g. Most metals are silvery looking, high density, relatively soft and easily deformed solids with good electrical and thermal conductivity, closely packed structures, low ionisation energies and electronegativities, and are found naturally in combined states. Metals appear lustrous (beneath any patina) form mixtures ( alloys) when combined with other metals tend to lose or share electrons when they react with other substances and each forms at least one predominantly basic oxide.
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