Metals

Metals are defined as the elements which form positive ions by the loss of electrons. Atoms of metals usually have 1, 2, or 3 electrons in their outermost shells. Metals are categorized on the basis of their characteristics into alkali metals, alkaline earth metals, Transition metals and Inner transition metals. The metals have been placed on the left side and in the middle of the Periodic Table. All alkali metals react with water to form their hydroxides which are strong alkalies. The oxides of alkaline earth metals occur in the earth’s crust and their hydroxides are alkalies. All metals are solid at room temperature except mercury and gallium which are liquid. They have high density and possess lustre. Most of the metals are hard and strong except sodium and potassium which can be cut with a knife. Metals possess high melting and boiling points and vaporize only at high temperatures. They are usually ductile and malleable. Metals are hard but not brittle. They are good conductors of heat and electricity. Metals form alloys and amalgams. Usually, metals do not dissolve in liquid solvents. Oxides of metals are usually basic. Metals above hydrogen in the activity series usually replace hydrogen from dilute acids. Metallic chlorides are electrovalent compounds that act as electrolytes. When electricity is passed through fused or aqueous solution of metallic chloride, metals are discharged at the cathode and chlorine at the anode. Metals ionize by loss of electrons and hence are reducing agents. Metals do not form hydrides. But if they form, they are not very stable.

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