Polyatomic Ions

It is also possible for several nonmetal atoms to cluster together in groups and form ions. They are called polyatomic ions. The formulas and charges of these polyatomic ions are not nearly so predictable as the simple anions you just studied. Nor are they all anions. The eight that you will need to memorize are listed here (and in example 8 in your workbook).

You need to know the names and formulas for these eight polyatomic ions.

Important Polyatomic Ions
Name Formula
acetate C2H3O2-
carbonate CO32-
nitrate NO3-
phosphate PO43-
sulfate SO42-
chlorate ClO3-
hydroxide OH-
ammonium NH4+

Note that nearly all have "-ate" endings.  Note that nearly all contain oxygen with one other element, and nearly all have negative charges.

Soon (by the end of this lesson) you should memorize these, but in the meantime use this list when you need to work with the names and formulas of these polyatomic ions.

 

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E-mail instructor: Eden Francis

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