An ionic compound is one which, when dissolved in water, forms a conducting solution.  Thus, it consists of positive and negative ions.  Follow these steps in writing formulas:

Find the positive ion on the chart.  It is named first.

Find the negative ion on the chart.  It is named second.

Balance the positive and negative charges by placing superscript numbers following each ion.  (Every compound is electrically neutral.)

   Example:

   sodium sulfate                    aluminum hydroxide                tin (II) chloride

    Na⁺¹    SO₄^-2                        Al⁺³            OH^-1                    Sn⁺²        Cl^-1

        Na₂SO₄                                  Al(OH)₃                                   SnCl₂

         (+2, -2)                                    (+3, -3)                                  (+2, -2)

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