Ions And Formula

Worked Examples

Example-1
Write the Formula of oxide of elements ‘X’ when its Valency is 3
Solution 
    Symbols :    X    O
    Valencies :    3    2
            (Formula)

Example-2
If an Element ‘E’ has valency of 2.
i) What will be the formulae of it’s hydroxide ?
ii) What will be the formulae of its sulphide ?
Solution     
i) Formulae of hydroxide of elements ‘E’ 
        Symbols :    E    0H
        Valencies :    2    1
              
        Cross-over valencies. 
            E₁  OH₂     (or)    E (OH)₂
Formulae of hydroxide is E (OH)₂

ii) Formulae of Sulphide of element ‘E’ 
        Symbols :    E    S
        Valencies :    2    2
            
        Cross-over valencies. 
            E₂  S₂        (or)    ES
Formulae of Sulphide is ES

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