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Friday, June 3, 2016

Simple Rules in Naming Chemical Compounds

A. Binary Compounds of Metal and Nonmetal
     This compound is composed of metal and nonmetal. If you want to learn how to name this compound just follow the simple rule below:

     Rule:  Name of metal  + Stem name of nonmetal + -ide ending
   
     Example:
          NaCl    =          Na           +        Cl
                       =      Sodium       +       Chlor (stem name of chlorine) +  ide
                       =      Sodium Chloride

     Some more examples:
         KCl       =   Potassium chloride
         MgO     =   Magnesium oxide
         Li2S      =   Lithium sulfide
         MgCl2  =   Magnesium chloride
         BeO     =   Berrylium oxide

B.  Binary Compounds of Nonmetal and Nonmetal
      This compound is composed of two nonmetals.  Now in naming this compounds prefixes are used.

 Prefixes

     1     -   mono
     2     -   di
     3     -   tri
     4     -   tetra
     5     -   pent
     6     -   hex
     7     -   hept
     8     -   oct
     9     -   nona
    10    -   dec

     Rule:  Prefix of first element except mono +  Name of first nonmetal + Prefix of second nonmetal + stem name of second nonmetal + ide

     Example: 

     CO =      C         +          O
           =    Carbon (1 carbon no prefix since mono)  +  Mono (1 oxygen ) + ox (stem name of oxygen) + ide 
           =    Carbon monoxide

     Other examples:
      
      CO2    -   Carbon dioxide
      NO3    -   Nitrogen trioxide
      N2O4  -   Dinitrogen tetraoxide
      CCl4   -   Carbon tetrachloride
      P2O4   -   Diphosphorus tetraoxide

C.  Binary Acids 
     This compound is composed of hydrogen bonded to a nonmetal

     Rule :  Hydro (constant prefix) + stem name of nonmetal + -ic acid

     Example :
 
    HCl   =          H          +         Cl
              =     Hydro   +   chlor  (stem name of chlorine) +  ic acid
              =    Hydrochloric acid

     Other examples;
     H2S    -   Hydrosulfuric acid  ( sulfur is exempted to the rule, full name is used)
     HF      -   Hydroflouric acid
     HBr    -   Hydrobromic acid


D.  Binary compounds of metal with variable oxidation number and nonmetal
      This compound is composed of metal having two or more oxidation number paired with a nonmetal.

     There are two rules to follow, one is by the use of IUPAC system of naming and the latin system of naming.

IUPAC System:

     Rule :  Name of metal + Roman Numeral showing the oxidation used in metal element +  Stem name of nonmetal  +  ide

     Example :

     FeCl2   =     Fe (+2 oxidation used)      +   Cl  (-1 oxidation used)
                 =     Iron (II) (II - indicates the oxidation number used of Fe)  +  Chlor (Stem name of chlorine + ide
                 =     Iron (II) chloride

     Other examples:

     FeCl3    -  Iron (III) chloride
     Fe2O3    -  Iron (III) oxide
     FeO      -  Iron (II) oxide

  Latin System:

     Rule :  Stem name of the latin name of metal ( but there are some exemption like Hg)  + ic ( is attached when the oxidation number used of the metal is higher) or  -ous (is attached when the oxidation number used of the metal is lower) + stem name of nonmetal + ide

     Example:

     FeCl2   =     Fe (+2 oxidation used)    +      Cl   (-1  oxidation used)
                  =    Ferr  ( Stem name of the latin name of Fe which is Ferrum)  +  ous ( ous is the suffix used for lower oxidation number  +  chlor (stem name of chlorine)  +  ide
                  =    Ferrous chloride
 
     Other examples:
   
     FeCl3     -   Ferric chloride
     Fe2O3     -   Ferric oxide
     FeO        -  Ferrous oxide

E.  Ternary Ionic Compounds
      This compound is composed of metal attached to a  polyatomic anion.

     Rule:   Name of metal ( use roman numeral of the oxidation number when metal has variable oxidation number +  name of the polyatomic anion.

     Example :

     NaOH   =     Na        +          OH
                  =    Sodium (the name of the metal)  + hydroxide ( name of the polyatomic anion)
                  =    Sodium hydroxide

     Other Examples:

     CaSO4        -  Calcium Sulfate
     Cu3PO4      -  Copper (I) phosphate
     Cu3(PO3)2 -  Copper (II)  phosphite


F. Ternary Acids (Oxyacids)
     Ternary acids are acids composed of hydrogen element paired to polyatomic anion.  This is also called oxyacids, acids containing oxygen.

     Rule :  Stem name of the element which is not hydrogen and oxygen (but there are some exemption, other element use full name like sulfur, carbon) + ous acid ( this is used when the ending of the polyatomic anion is ite) or ic acid (when the ending name of the polyatomic anion is ate).

     Example

     H2SO4   =       H      +    SO4  (sulfate, name of polyatomic anion)
                  =     Sulfur    +   ic acid ( ic acid is used because sulfate ends in ate)

     Other examples:

     H3PO3    -   Phosphorous acid
     H3PO4    -   Phosphoric acid
     H2SO3    -   Sulfurous acid


Try your knowledge by answering Pactice Test. Click  NAMING OF COMPOUNDS WORKSHEET













     
       
                   

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