metal

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Any of a class of chemical elements with specific physical and chemical characteristics. Metallic elements compose about 75% of the 112 elements in the periodic table of the elements.

Physical properties include a sonorous tone when struck; good conduction of heat and electricity; high melting and boiling points; opacity but good reflection of light; malleability, which enables them to be cold-worked and rolled into sheets; and ductility, which permits them to be drawn into thin wires.

The majority of metals are found in nature in a combined form only, as compounds or mineral ores; about 16 of them also occur in the elemental form, as native metals. Their chemical properties are largely determined by the extent to which their atoms can lose one or more electrons and form positive ions (cations).

All metals except mercury are solid at ordinary temperatures, and all of them will crystallize under suitable conditions. The chief chemical properties of metals also include their strong affinity for certain non-metallic elements, for example sulphur and chlorine, with which they form sulphides and chlorides. Metals will, when fused, enter into the forming of alloys.

By comparing the reactions of metals with oxygen, water, acids, and other substances, the metals can be arranged in order of reactivity, known as the reactivity series of metals.

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