Chapter 4 Compounds and Their Bonds 4.4 Polyatomic Ions 1 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Polyatomic Ions are a group of atoms with an overall charge often consist of a nonmetal such as phosphorus, sulfur, carbon, or nitrogen and oxygen usually have a 1−, 2−, or 3− charge 2 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Names of Polyatomic Ions 1.Names of most common polyatomic ions end in ate. SO 4 2− sulfate PO 4 3− phosphate NO 3 − nitrate 2.When a related ion has one less oxygen, its name ends in ite. SO 3 2− sulfite PO 3 3− phosphite NO 2 − nitrite 3 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Names of Polyatomic Ions 3.Exceptions to these rules are: CN − cyanide OH − hydroxide NH 4 + ammonium 4.Add an H + and reduce negative charge. CO 3 2− + H + =HCO 3 − carbonate+ H + =bicarbonate or hydrogen carbonate SO 4 2− + H + =HSO 4 − sulfate+ H + =bisulfate or hydrogen sulfate 4 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Names of Polyatomic Ions 5. Halogens form 4 polyatomic ions with oxygen each have a  1 charge. ClO 4 − perchlorate ClO 3 − chlorate ClO 2 − chlorite ClO − hypochlorite 5 Sodium chlorite is used in the processing and bleaching of pulp from wood fibers and recycled cardboard. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Compounds Containing Polyatomic Ions When writing formulas for ionic compounds containing polyatomic ions, we use the same rules of charge balance as those for simple ionic compounds. Consider the formula for magnesium nitrate: Mg 2+ + NO 3 − NO 3 − (2+) + 2(1−) = 0 Mg NO 3 − = Mg(NO 3 ) 2 6 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Learning Check Select the correct formula for each. A. aluminum nitrate 1) AlNO 3 2) Al(NO) 3 3) Al(NO 3 ) 3 B. copper(II) nitrate 1) CuNO 3 2) Cu(NO 3 ) 2 3) Cu 2 (NO 3 ) C. iron(III) hydroxide 1) FeOH2) Fe 3 OH3) Fe(OH) 3 D. tin(IV) hydroxide 1) Sn(OH) 4 2) Sn(OH) 2 3) Sn 4 (OH) 7 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Solution Select the correct formula for each. A. aluminum nitrate 3) Al(NO 3 ) 3 B. copper(II) nitrate 2) Cu(NO 3 ) 2 C. iron(III) hydroxide 3) Fe(OH) 3 D. tin(IV) hydroxide 1) Sn(OH) 4 8 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Guide to Naming Ionic Compounds with Polyatomic Ions 9 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Naming Compounds with Polyatomic Ions Name the following ionic compounds: Step 1Step 2Step 3 Step 4 cation/anionNameName Name cationanion compound A.Ca(NO 3 ) 2 Ca 2+ NO 3 − calciumnitratecalcium nitrate B.FePO 4 Fe 3+ PO 4 3− iron(III)phosphateiron(III) phosphate 10 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Learning Check Name each of the following compounds containing polyatomic ions. A. MgSO 3 B. MgSO 4 C. Ca(ClO 3 ) 2 11 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Solution Name the following ionic compounds: Step 1Step 2Step 3 Step 4 cation/anionNameName Name cationanion compound A. MgSO 3 Mg 2+ SO 3 2− magnesiumsulfitemagnesium sulfite B. MgSO 4 Mg 2+ SO 4 2− magnesiumsulfatemagnesium sulfate C. Ca(ClO 3 ) 2 Ca 2+ ClO 3 − calciumchloratecalcium chlorate 12 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Learning Check Name each of the following compounds: A.Fe 2 (SO 4 ) 3 B.Ba 3 (PO 3 ) 2 C.PbCO 3 13 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.

Solution Name the following ionic compounds: Step 1Step 2Step 3 Step 4 cation/anionNameName Name cationanion compound A. Fe 2 (SO 4 ) 3 Fe 3+ SO 4 2− iron(III)sulfateiron(III) sulfate B. Ba 3 (PO 3 ) 2 Ba 2+ PO 3 3− bariumphosphitebarium phosphite C. PbCO 3 Pb 2+ CO 3 2− lead(II)carbonatelead(II) carbonate 14 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.