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Chapter – 4
Materials: Metals and Non-Metals Metals arestrong and durable. Thus metals areused so widely for making almost everything Example: Metals areused in making machinery, automobiles, aeroplanes, buildings, trains, satellites, gadgets, cooking utensils, water boilers...etc. Physical Properties of Metals The metal basein an electric iron is forconducting heat, notelectricity. Metals are very good conductors of heat. Cooking utensils, irons, heaters, etc. are all made ofmetals which aregood conductors ofheat. Metals can be easily shaped into wires. This property of metals is called ductility. Metals can be easily shaped into thinflat sheets. Thischaracteristic of metals is called malleability. Metals make asound when struck with hard objects. Metals can bepolished to ashiny appearance.
Chemical Properties of Metals
metals react with oxygen to produce metal oxides which are basic in nature. Non- metals react with oxygen to produce non-metallic oxides which are acidic in nature. Some metals react withwater to produce metal hydroxides andhydrogen gas.
Generally, non- metals do not reactwith water.
Metals react withacids and produce metal salts andhydrogen gas. Generally, non- metals donot react withacids.
Some metals react with bases toproduce hydrogen gas.
More reactive metals displace lessreactive metals fromtheir compounds inaqueous solutions
Physical Properties of Non-metals
Non-metals are non-lustrous, non-malleable and notductile, except forcarbon fibres, which are ductile. Non-metals are not sonorous. They do not produce any sound when hit.. Non-metals donot conduct heatand electricity except for graphite
Chemical Properties of Non-metals·
Non-metals reactwith oxygen toform their oxides. Non-metal oxides areacidic or neutral in nature. In general non-metals do notreact with waterthough they maybe very reactive in air. Non-metals do notreact with acids Metals andnon-metals are usedwidely in every day life.
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