Notes C - 2, Metals and non metals

Physical Properties of Metal

-   Metals are Lustre means they have shiny surface

-   Metals are generally hard. Except – Sodium, Lithium and Potassium

-   Metals are found in solid state. Except – Mercury

-   Metals are Malleable it means metals can be beaten into thin sheets

                Gold  and silver are most malleable metals

-   Metals are ductile it means metals can be drawn into thin wires.

-   Metals are good conductor of heat and electricity

                Silver and Copper are best conductor of Heat and Electricity

-   Metals have high density that’s why metals melting point is high.

                Except -  Sodium and Potassium

-   Metals are Sonorous means metals produce sound when strike by a hard surface

-   Metal oxides are basic in nature.

Physical Properties of Non- Metal

-   Non- Metals are not Lustre means they do not have shiny surface

                 Except -  Iodine

-   Non- Metals are generally soft.

Except –  Except diamond ( it is a form of carbon)

-   Non- Metals are exist in solid or gaseous  state.

 Except – Bromine (liquid)

-   Non- Metals are not Malleable it means Non-  metals can’t  be beaten into thin sheets

-   Non- Metals are non ductile it means Non- metals can’t be drawn into thin wires.

-   Non- Metals are poor conductor of heat and electricity

-   Non- Metals have high density that’s why Non- metals melting point is very low. 

-   Non- Metals are not Sonorous means Non- metals do not produce any sound when strike by a hard surface

-   Non- Metal oxides are acidic in nature.

Chemical Properties of Metals

(A) Reaction with Air – Metal combine with oxygen to form metal oxide.

                Metal   +   Oxygen →  Metal Oxide

Ex – (i)  2Cu   +   O₂    →     2CuO

        (ii)  4Al   +  3O₂   →  2Al₂O₃

        (iii)  2Mg  +  O₂   →   2MgO

Different Metals show different reactivitie towards Oxygen (O₂)

(i)  Sodium (Na) and Potassium (K) react so vigorously that they catch fire if kept in open so they are kept immersed in kerosene.

(ii)  Surfaces of Magnesium (Mg), Aluminium (Al), Zinc( Zn), Lead (Pb) are covered with a thin layer of oxide which prevent them from further oxidation

(iii)  Fe does not burn on heating but iron fillings burn vigorously

(iv)  When Copper is heated it does not burn but is coated with black copper oxide

(v)  Gold (Au) and Silver (Ag) does not react with oxygen 

Amphoteric Oxides

Metal oxides which react with both acids as well as bases to produces slats and water are called amphoteric oxides.

Ex –

         Al₂O₃  +  6HCl →  2AlCl₃  +  H₂O

        Al₂O₃  +  2NaOH →  2NaAlO₂  +  H₂O

(B) Reaction of Metals with water (H₂O)

Metal  +  Water  → Metal Oxide  + Hydrogen

Metal  Oxide  +  Water  →  Metal hydroxide

Ex –

     (i)  2Na  +  2H₂O  →    2NaOH  +  H₂  +  Heat

     (ii)  Ca  +  2H₂O  →  Ca(OH)₂  +  H₂

     (iii)  Mg  +  2H₂O  →  Mg(OH)₂  +  H₂

     (iv)  2Al  +  3H₂O  →  Al₂O₃  +  3H₂

>  Al, Fe and Zn React with stem

>  Na, K and Ca react with cold water

>  Mg react with hot water

>  Ca and Mg float as bubbles of Hydrogen stick to their surface

>  Pb, Cu, Au and Ag not react with water

(C)  Reaction of Metals with Acids

Metal   +  Dilute acid  →   Salt  +  Hydrogen

Cu, Ag and Hg do not react with dilute acids.

Ex –

     (i)  Fe  +  2HCl  →  FeCl₂  +H₂

     (ii)  Mg  +  2HCl  →  MgCl ₂  + H₂

     (iii) Zn  + 2HCl  →  ZnCl₂  +  H₂

(D) Reaction of Metals with Solutions of other Metals Salts

Metal A   +  Salt solution B    →   Salt solution A  + Metal B

*Reactive metals can displace less reactive metals form their compounds in solution form.

Ex -    Fe  +  CuSO₄   →   FeSO₄  +Cu

REACTIVITY SERIES

Reactivity series arranged in decreasing order from upper to lower of their reactivity

Symbols	Name
K	Potassium	Most Reactive Moderate Reactive Least  Reactive
Na	Sodium
Ca	Calcium
Mg	Magnesium
Al	Aluminium
Zn	Zinc
Fe	Iron
Pb	Lead
H	Hydrogen
Cu	Copper
Hg	Mercury
Ag	Silver
Au	Gold

Reaction of Metals with Non-Metals

Reactivity of elements is the tendency to attain a completely filled valence shell

Atoms of the metals loses electrons from their valence shell to form cation

Atoms of the non-metal gain electrons in the valence shell to form anion

Ex –

Formation of NaCl

Na ➔ Na⁺ + e^-  (Sodium cation)

2,8,1         2,8

Sodium cation

Cl + e^-  ➔  Cl^-   (Chlorine anion)

2,8,7               2,8,8

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Ionic Compounds

The compounds formed by the transfer of electron form a metal to a non-metal are called ionic or  electrovalent compound.

Physical Properties of Ionic Compounds

1- Physical Nature -  They are solid and hard, generally brittle.

2- Melting and Boiling Point – They have high melting and boiling point.

3- Solubility – Generally soluble in water and insoluble in such solvent like petrol or kerosene

4- Conduction of Electricity – Ionic compounds conduct electricity in molten and solution state but not in solid state.

Occurrence Of Metals

Minerals -  The elements or compounds which occur naturally in the  earth’s crust are called minerals

Ores – Minerals that contain very percentage of particular metal and the metal can be profitable extracted from it, such minerals are called ores. 




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