Formulea of Ionic Compounds

Formulea of Ionic Compounds

Author: Angela Nichols

Students will learn how to categorize ions and write the chemical formula of ionic compounds.

This packet includes a video, a table of cations, a table of anions, and the steps needed to determine the chemical formula of an ionic compound.

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Formulas of Ionic Compounds

Writing the Chemical Formula of an Ionic Compound

1) Look at a table to identify the charge sign, charge magnitude, and atomic symbol of each ion

2) Determine the relative abundance of each ion

       a)  Identify the smallest number that is a multiple of both charge magnitudes.  This is the least common multple (LCM).

       b) Calculate the subscript of the cation by dividing the LCM by the charge magnitude of the cation.

       c) Calculate the subscript of the anion by dividing the LCM by the charge magnitude of the anion.

3) Write the symbol of the cation first and the anion second.  Include subscripts, but only if the subscript is greater than one.

4) Put parenthesis around the symbol of polyatimc ions in order to distinguish ions and subscripts.

Table of Cations

Table of Anions

Independent Practice Solutions