Metals and non-metals / CBSC Class 8 NOTES

 Metals and non-metals/CBSC Class 8 NOTES

 

 
 



class 8 and class 10 questions and answer
Metals and non-metals/CBSC Class 8 NOTES

 PHYSICAL PROPERTIES OF METALS AND NON-METALS

 

Physical Properties Include Physical State , Lustre , Colour , Hardness , Mallealibity , Ductility , Thermal Conductivity , Eletrical Conductivity ,and Sonority.
  • PHYSICAL STATE

 

PHYSICAL STATE MEANS METALS AND NON-METALS ARE SOLID
  AT ROOM TEMPERATURE .

  • METALS –   Amost All metals ARE SOLID AT ROOM TEMPERATURE  .MERCURY IS AN EXCEPTION BECAUSE IT IS KNOWN TO OCCUR IN A LIQUID STATE AT OR NEAR ROOM TEMPERATURE 



  • NON-METALS – ALMOST ALL NON-METALS ARE SOLID OR GASES AT ROOM TEMPRATURE .

 

  • BROMINE  IS THE ONLY NON – METAL THAT IS LIQUID STATE AT ROOM TEMPERATUIRE .

  • LUSTRE
LUSTRE MEANS METALS AND NON- METALS GIVE SHINE AND BECAUSE OF THAT IT REFLECT LIGTH.

  • METALS – ‘ LUSTRE ‘ OR A SHINY SURFACE IS APROPERTY OF MOST METALS .
 THIS IS BECAUSE METALS CAN BE POLISHED . BECAUSE OF THEIR ABILITY TO SHINE AND REFLECT  LIGTH ,  METALS LIKE GOLD , SILVER ,  AND  PLATINUM ARE USED FOR MAKING JEWALERY AND OTHER DECORETIVE ARTICLES.



  • NON-METALS – ALMOST ALL NON-METALS ARE HAVE DULL SURFACE . 


AS MOST FO THEM OCCUR AS POWERS AND GASES , THEY CANNOT BE POLISHED LIKE METALS . GRAPHITE (A FORM OF CARBON ) AND IODINE DO SHOW SOME LUSTRE .

  • COLOUR
COLOUR MEANS THAT THE COLOUR OF METALS AND NON-METALS .
 

  •   METALS – MOST METALS ARE WHITE OR SHILVERY – GREY . THERE ARE, HOWEVER , A FEW EXCEPTIONS. FOR EXAMPLE , GOLD IS YELLOW AND COPPER IS REDDISH-BROWN.

  •  NON-METALS – SOME NON-METALS ARE COLOURLESS WHILE SOME ARE COLOURED . 
FOR EXAMPLE ,CHLORINE IS A GREENISH-YELLOW GAS,BROMINE
IS A BROWN LIQUID , IODINE IS A VIOLET SOLID AND OXYGEN AND NITROGEN ARE COLOURLESS.



 

  • HARDNESS

 

HARDNESS MEANS THAT THE HARDNESS OF METALS AND NON-METALS.

  • METALS – Most of the metals are hard but some are in exception SODIUM and POTASSIUM are so soft that they can be cut with a knife.
  •  NON-METALS – Non-metals are soft but DIAMPND is a form of carbon ,is an exception .It is the hardest supstance known in the world. 
  • MALLEABILITY

 

MALLEABILITY MEANS THAT METALS AND NON METALS ARE  CONVERT INTO THIN SHEETS .

  •   METALS – Most of the metals are beaten into thin sheets or foils.GOLD , SILVER and ALUMINIUM are the common example of this.




  •  NON-METALS – Non-metals are cannot be beaten into thin sheets or foils.
  • DUCTILITY

 

DUCTILITY MEANS THAT METALS AND NON-METALS ARE CONVERT INTO THIN WIRES.

  •  METALS – Most  of the metals are can be covert into thin wires because they have a property that they can be convert into thin wires.COPPER, ALUMINIUM , GOLD and SILVER are the common example of this .

  •  NON-METALS – Non-metals are cannot be convert into yhin wires .
  • THERMAL CONDUCTIVITY
THERMAL CONDUCTIVITY MEANS THAT METALS AND NON-METALS ARE GOOD CONDUCTOR OF HEAT.

  •  METALS – Metals are good conductor of heat ,they are used for making cooking utesils. SILVER is the best conductor of heat , after sivler, COPPER is the good conductor of heat .



NON-METALS – Non-metals are poor conductor of heat ,therefore , DIAMOND good conductor of heat which is in the exception .
  • ELECTRICAL CONDUCTIVITY 

ELECTRICAL CONDUCTIVITY MEANS THATE METALS AND NON METALS ARE GOOD CONDUCTOR OF ELECTRICITY.

  •  METALS – Metals are good conductor of electricity and they are used for making electrical wires and cables .

  •  NON-METALS – Non-metals nare poor conductor of good conctor of electricity but graphite is a good conductor of electricity which is in exception.
  • SONORITY
SONORITY MEANS THAT METALS AND NON-METALS PRODUCE A RINGING SOUND .



  •  METALS – When metal object struck with a hard object it make ringing sound because metals have a property of ringing sound .Objects like WIND CHIMES and BELLS make use to produce ringing sound 

  •  NON-METALS – Non-metals dosenot produce ringing sound when they struck with hard object .
 
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