Metals and Non-metals| Its properties|their group|

   Metals & Non- Metals 

Metals 

   A metal is defined as an element which can form positive ions by the loss of electrons. For Example :- Sodium, magnesium and aluminium are metals because they form positive ions by the loss of 1,2 and 3 electrons respectively. 

Categorisation of Metal 

         Metal have been categorised on the basis of their characteristics. In the periodic table, metals have been placed on the left hand side while Non-metals have been placed on the right side. Only one Non-metals, that is hydrogen has been placed on the left side. Metalloids(which show both metal and non-metals Properties) have been placed between the metals and Non-metals.

Metallic character of element decreases as we move from left to right in the periods of the periodic table

Alkali metals

        Elements having one electron in their outermost orbit like lithium (Li), Sodium (Na), potassium (K), that are placed the first column on the left of the periodic table and show one valency, are known as Alkali metals, as they react with water to form their hydroxides which are strong alkalies. 

Hydrogen is also placed in this group as it has one electron, but it is an exception. It is not an alkali metal. 

Alkaline Earth Metal 

       Element such as Beryllium (Be), calcium (Ca), Barium (Ba), strontium(Sn) and radium(Ra) having two electrons in their outermost orbits that show valency two, are known as alkaline earth metals, because their oxides in the earth's crust and their hydroxides are alkalies. Since alkaline earth metals are reactive metals (but less reactive than alkali metals, therefore, they are not occur free in nature.

Transition Metals

    They are placed in the middle of the periodic table. Mostly they have two electrons in their valence shell. Their two outermost shells are incomplete.        Transition metals are hard and heavy and are metals with heavy and are metals with high melting and boiling points and are good conductors of heat and electricity. 

Inner Transition Metals

     They are placed at the bottom of the periodic and are  heavy metals with high melting  and boiling points. 

Properties of Metals

 Physical State :- At room temperature, all metals are solid except mercury which is a liquid and gallium which changed to liquid when handled. 

Hardness :- Most of the metals are hard and strong. (Exception - sodium and potassium which are so soft that they can be cut with a knife). 

Lustre:- Metals are lustrous, that is, shiny this property is called lustre. Metals can be polished to give a highly reflective surface. (Exception : lead is a metal with dull Appearance). 

Melting & Boiling Points:- Usually metals possess high melting and boiling point and Vaporise only at high temperature.  (Exception:- Gallium, mercury, sodium, and potassium) 

Density :- Metals  have a high density which means they are heavy.                       (Exception : sodium and potassium) 

Ductility :- Ductile means which can be stretched or drawn into thin wire without breaking. Metals are usually ductile.               For example, it has been possible to draw silver wires of 0.0008 mm diameters. Tungsten can de drawn into such fine wires that they become almost invisible. (Exception:- Zinc, mercury, and gallium). 

Malleability :- Malleable means which can be beaten with hammer to form thin sheets without breaking. Metals are usually malleable ( Exception:- Zinc and mercury) . Silver and Gold are highly malleable. It has been possible to beat bold into foil less than 0.0001  mm in thickness. 

Brittleness :- Brittle means which breaks into peaces on hammering or stretching. Metals are hard but not brittle ( Exception:- Zinc). 

Tensile Strength:- By tensile strength means ability to withstand stress. Generally, metals have tensile strength. 

Conductivity:- Except Bismuth all metals are good conductor of both heat and electricity. Silver, is the best conductor followed by copper and aluminium. 

Sonority:- Metals are sonorous which means that they make a ringing sound when they struck with a hard object  this property of sonority in made use of an objects such as wind chimes and bells. 

Solubility:- Usually metals do not dissolve in liquid solvents. 

Alloys or Amalgam:- Metals mix with each other in molten state and then form alloys on Solidification with thay form amalgams. 

Alloys-Stainless Steel
Composition- Iron, Chromium, Nickel

Non- Metals

      It is defined as an element which can accept one or more electrons and then form negative ions (anions).         (Examples :- Chlorine is a non-metals since it accept one electron and forms Cl- and oxygen is a non-metals since it accept 2 electrons and forms oxide ion. 

Properties of Non-Metals 

Physical State :- Non-metals may exist in all three states--- solids, liquid or gas. Only one non-metals Bromine is a liquid.   Carbon, Sulphur and Iodine are solids. Nitrogen, oxygen, hydrogen are gases st room temperature. 

Hardness :- Some solid non-metals like sulphur and phosphorus are soft, whereas, some are Hard.  Diamond— a non-metals and an allotrope of carbon is the hardest naturally occurring substance known. 

Lustre :- Non-metals have a dull appearance, except iodine and graphite whose crystals are quite lustrous. The sparkle of diamond is well known. 

Melting & Boiling Points:-  Non-metals have low melting points. They vaporise at low temperatures. (Exception:- silicon,carbon, boron) 

Density :- Non-metals have low densities. (Exception:- iodine has a density higher than that of many metals. Diamond has a high density). 

Ductility:- Ductility means which  can be stretched or drawn into thin wires without breaking. Non-metals are not ductile except carbon fibre. 

Malleability:-  Malleable means which can be beaten with a hammer to form thin sheets without breaking. Non-metals are not malleable in solid form i.e., they break into peaces when hammered. 

Brittleness :- Brittle means which breaks into pieces on hammering or stretching. Non-metals are generally brittle. 

Tensile strength:- Which means ability to withstand stress.Non-metals, generally, have low or very low tensile strength. 

Conductivity:- Non-metals except graphite are non-conductors if heat and electricity. Most non-metals are used as insulators. 

Sonority :- Sonorous which means that they make a ringing sound when struck with a hard object. Except for special stones, all metals are non-sonorous they produce only a dull sound on being hit. 

Solubility:- Non-metals dissolve in many liquids solvent, e.g., sulphur dissolves in carbon disulphide and iodine in chloroform. 

Alloys or Amalgams :- They do not form alloys and amalgams. (Exception carbon and Phosphorus can be used in alloys). 

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