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Polyatomic Ions. Polyatomic ions are a group of covalently bonded atoms with an overall charge and a specified chemical formula. The name and charge of the ion refers to the entire group. The chemical formula of the polyatomic ion is treated as a unit in any overall
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Polyatomic Ions Polyatomic ions are a group of covalently bonded atoms with an overall charge and a specified chemical formula. The name and charge of the ion refers to the entire group. The chemical formula of the polyatomic ion is treated as a unit in any overall formula of a compound. For example, the polyatomic ion nitrate has the formula of NO3 and a charge of –1 ( NO3 -) For the compound magnesium nitrate, the formula of nitrate is treated as a unit, and the formula of the entire compound is written as: Mg(NO3)2
The formulas and charges of polyatomic ions are not easily predicted so you will be responsible for memorizing the names, formula, and charge of the following polyatomic ions. Anions OH – CO32 PO43 – NO3SO4 2 ClO3CrO4 2 – C2H3O2Cr2O7 2 – HCO3 MnO4 O2 2 CN Cations NH4 +
Polyatomic ions are named as a unit. Polyatomic anions that include oxygen use the “ate”, ending except for hydroxide. Polyatomic anions without oxygen use the “ide” ending.
Anions Cations OH – hydroxide NH4 + ammonium NO3nitrate ClO3chlorate C2H3O2 acetate HCO3 hydrogen carbonate MnO4 permanganate O2 2 peroxide CN cyanide CO32 carbonate SO4 2 sulfate CrO4 2 – chromate Cr2O7 2 – dichromate PO43 – phosphate