Metal, nonmetal or metalloids
The elements on the periodic table are classified as metals, nonmetals and metalloids according to their physical and chemical properties. A metals are usually shiny (metallic luster), malleable, ductile and are very good conductor of heat and electricity. Ductility is the ability of a solid to deform while being stretched; this is often characterized by its ability to be stretched into a wire. Malleability, a similar property, is the ability of a solid to deform under compressive stress; this is often characterized by the material's ability to form a thin sheet by hammering or rolling. Metals occupy most of the periodic table. Metals are sometimes described as an arrangement of positive ions surrounded by a sea of delocalized electrons. The produced solid is held by electrostatic interactions between the ions and the electron cloud, which is called metallic bond. Typically, metals tend to give off electrons during chemical reactions to form positive charged ions called cations. One way to identify a metal is by reaction with acid. If a metal is reacted with a hydrochloric acid solution (HClaq), the metal will be transformed to his chloride salt and will be completely dissolve in the aqueous solution. Most metals can react with oxygen (air) to form metal oxides. Some metals form barrier layers of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic. One way of determining if an aqueous solution is basic is by using phenofthalein. An acid solution (pH < 7) will be clear while a basic solution (pH > 7) will give a pick color. Non-metals are totally the opposite of metals. They are very poor conductors of heat and electricity when compared to metals. They are considered insulators. Most of the non-metals are gases while some can be solid and Bromine is...
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