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Introduction of Elements









 Elements:

In the early ages,only nine elements (carbon,gold,silver,tin,mercury,lead ,copper,iron and sulphur) were known.

At that time it was considered that elements were the substance that could not br broken down into simple units by ordianary chemical processes.Until the end of nineteenth century sixty three elements had been discovered.Now 118 elements have been discovered,out of which 92 are naturally occuring elements.Modern defination of elements is :

It is a substance made up of some type of atoms,having same atomic number and cannot be decomposed into simple substances by ordinary chemical means.

It means that each element is made uo of unique type of atoms that have very specific properties.

Elememts occur in nature in free or combined form.All the natually occuring elements found in the world have different percentage in the earth's crust,oceans and atomsphere. 



Elements may be soilds,liquid and gases.Majority of the elements exist as soilds e.g. sodium,copper,zinc and gold etc.There are very few elements which occur in liquid e.g. mercury and bromine.A few elements exist as gases e.g. nitrogen,oxygen,chlorine and hydrogen.On the basis of their properties,elements are divided into metals,non-metals and metalloids.About 80% of elements are metals.

Elements are represented by symbols,which are abbreviations for the name of elements.A symbol is taken from the name of that element in Enhlish,Latin,Greek or Greman.If it is one-letter,it will be capital as H fir Hydrogen.N for Nitrogen,C for Carbon etc.In case of two letters symbol,one first letter is capital e.gnCa for Calcium,Na for Sodium and Cl for Chlorine.






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