Materials: Metals And Non-Metals

  

Topic Name      : Materials: Metals And Non-Metals.

Class                    : VIII^th Standard.

Subject               : Chemical Sciences.

ELEMENT                  : It is defined as a species of atoms that the same number of protons in                                                their  atomic Nuclei.

                                            

METAL                  : A metal is an element that readily forms positive ions (cations) and has    metallic bonds. Metals are sometimes described as a lattice of positive ions surrounded by a cloud of delocalized electrons.

 

NON METAL                : Non-metals are those substances which are generally soft, non-lustrous, non-malleable , non-ductile, not sonorous and poor conductors of heat and electricity.

 

DIFFERENCES BETWEEN METALS AND NON-METALS

 

METALS                                                                                 NON- METALS Ø  They are solid at room temperature.              They may be solid, liquid or gas at room temp Ø  They have high melting and boiling points.     They have low melting and boiling points.

PHYSICAL PROPERTIES OF METALS: Ø  Corrosion resistance. Ø  Density. Ø  Melting point.   CHEMICAL PROPERTIES OF METALS : Ø  The density of metals is usually high. Ø  Metals are malleable and ductile. Ø  Metals form an alloy with other metals or non – metals.  PHYSICAL PROPERTIES OF NON METALS : Ø  High ionization energies. Ø  High electron Negativities. Ø  Poor thermal conductors.   CHEMICAL PROPERTIES OF NON METALS : Ø  A non-metal does not react with water, but it is usually very reactive in air, so some are stored in water. Ø  None of the non-metals is known to react with acids. Ø  The reaction between non-metals and bases is a very complex one. The reaction of chlorine with bases like sodium hydroxide gives products like sodium hypochlorite, sodium chloride as well as water.   USES OF METALS AND NON METALS :  METALS : Ø  Lead metal is used in making car batteries. Ø  Zinc is used for galvanizing iron to protect it from rusting. Ø  Iron, copper and aluminium are used to make utensils. Ø  Copper and aluminium metals are used to make electrical wires. NON METALS: Ø  For the preparation of ammonia, nitric acid and fertilizers, nitrogen is used. Ø  For the purification of water, chlorine is used. Ø  Hydrogen is very useful as rocket fuel. Ø  Carbon can be used to make pencils when it is in graphite form. Ø  Sulphuric acid is prepared using sulphur.   IMPORTANT LINKS :   Ø  https://www.youtube.com/watch?v=nVUm7Wqa608   VARIOUS PICTURES OF METALS :   ACTIVITIES DONE BY THE STUDENTS :

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