9.1 Naming Ions > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 9 Chemical Names and Formulas 9.1 Naming Ions 9.2 Naming and Writing Formulas for Ionic Compounds 9.3 Naming and Writing Formulas for Molecular Compounds 9.4 Naming and Writing Formulas for Acids and Bases 9.5 The Laws Governing How Compounds Form

9.1 Naming Ions > 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Monatomic Ions How can you determine the charges of monatomic ions? Monatomic Ions

9.1 Naming Ions > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Some ions, called monatomic ions, consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons, respectively. Monatomic Ions

9.1 Naming Ions > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Recall that metallic elements tend to lose valence electrons. All the Group 1A ions have a 1+ charge (Li +, Na +, K +, Rb +, and Cs + ). Group 2A metals, including magnesium and calcium, tend to lose two electrons to form cations with a 2+ charge (Mg 2+ and Ca 2+ ). Aluminum is the only common Group 3A metal, and tends to lose three electrons to form a 3+ cation (Al 3+ ). Monatomic Ions Cations

9.1 Naming Ions > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number. The elements in Group 7A form anions with a 1– charge (7 – 8 = –1). Monatomic Ions Anions

9.1 Naming Ions > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Anion names start with the stem of the element name and end in -ide. For example, two elements in Group 7A are fluorine and chlorine. The anions for these nonmetals are the fluoride ion (F – ) and the chloride ion (Cl – ). Monatomic Ions Anions

9.1 Naming Ions > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The first three elements in Group 5A, nitrogen, phosphorus, and arsenic, can form anions with a 3– charge (5 – 8 = –3). These anions have the symbols N 3–, P 3–, and As 3– and are called, respectively, nitride ion, phosphide ion, and arsenide ion. Monatomic Ions Anions

9.1 Naming Ions > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The charges of the cations of many transition metal ions must be determined from the number of electrons lost. For example, the transition metal iron forms two common cations, Fe 2+ (two electrons lost) and Fe 3+ (three electrons lost). Cations of tin and lead, the two metals in Group 4A, can also have more than one common ionic charge. Monatomic Ions Metals That Form More Than One Ion

9.1 Naming Ions > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. In the Stock system, you place a Roman numeral in parentheses after the name of the element to indicate the numerical value of the charge. For example, the cation Fe 2+ is named iron(II) ion and is read “iron two ion.” No space is left between the element name and the Roman numeral in parentheses. The Fe 3+ ion is named iron(III) ion and is read “iron three ion.” Monatomic Ions Metals That Form More Than One Ion

9.1 Naming Ions > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. An older, less useful method for naming these cations uses a root word with different suffixes at the end of the word. The older, or classical, name of the element is used to form the root name for the element. For example, ferrum is Latin for iron, so ferr- is the root name for iron. Monatomic Ions Metals That Form More Than One Ion

9.1 Naming Ions > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. An older, less useful method for naming these cations uses a root word with different suffixes at the end of the word. The suffix -ous is used to name the cation with the lower of the two ionic charges. The suffix -ic is used with the higher of the two ionic charges. Using this system, Fe 2+ is the ferrous ion, and Fe 3+ is the ferric ion. Monatomic Ions Metals That Form More Than One Ion

9.1 Naming Ions > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Monatomic Ions A major disadvantage of using classical names for ions is that they do not tell you the actual charge of the ion. Symbols and Names of Common Metal Ions With More Than One Ionic Charge SymbolStock NameClassical Name Cu 2+ Copper(I) ionCuprous ion Cu 2+ Copper(II) ionCupric ion Pb 2+ Lead(II) ionPlumbous ion Pb 4+ Lead(IV) ionPlumbic ion

9.1 Naming Ions > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. A few transition metals have only one ionic charge. The names of these cations do not have a Roman numeral. These exceptions include silver, with cations that have a 1+ charge (Ag + ), as well as cadmium and zinc, with cations that have a 2+ charge (Cd 2+ and Zn 2+ ). Monatomic Ions Metals That Form More Than One Ion

9.1 Naming Ions > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Polyatomic Ions How do polyatomic ions differ from monatomic ions? How are they similar? Polyatomic Ions

9.1 Naming Ions > 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Unlike a monatomic ion, a polyatomic ion is composed of more than one atom. But like a monatomic ion, a polyatomic ion behaves as a unit and carries a charge. Polyatomic Ions

9.1 Naming Ions > 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The sulfate anion consists of one sulfur atom and four oxygen atoms. These five atoms together comprise a single anion with an overall 2– charge. The formula is written SO 4 2–. Polyatomic Ions

9.1 Naming Ions > 17 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. You can see the structure of the sulfate ion along with three other common polyatomic ions below. Polyatomic Ions Ammonium ion (NH 4 + ) Nitrate ion (NO 3 – ) Sulfate ion (SO 4 2– ) Phosphate ion (PO 4 3– )

9.1 Naming Ions > 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The names and formulas of some common polyatomic ions are shown here. Note that the names of most polyatomic ions end in -ite or -ate. Polyatomic Ions Common Polyatomic Ions ChargeFormulaName 1– HSO 4 – NO 2 – ClO – Hydrogen sulfate Nitrite Hypochlorite 2– SO 3 2– SO 4 2– CO 3 2– Sulfite Sulfate Carbonate 3– PO 4 3 – Phosphate 1+NH 4 + Ammonium

9.1 Naming Ions > 19 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. For example, notice the endings of the names of the hypochlorite ion (ClO – ) and the carbonate ion (CO 3 – ). Polyatomic Ions Common Polyatomic Ions ChargeFormulaName 1– HSO 4 – NO 2 – ClO – Hydrogen sulfate Nitrite Hypochlorite 2– SO 3 2– SO 4 2– CO 3 2– Sulfite Sulfate Carbonate 3– PO 4 3 – Phosphate 1+NH 4 + Ammonium

9.1 Naming Ions > 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Sometimes the same two or three elements combine in different ratios to form different polyatomic ions. Look for pairs of ions for which there is both an -ite and an -ate ending, for example, sulfite and sulfate. Polyatomic Ions Common Polyatomic Ions ChargeFormulaName 1– HSO 4 – NO 2 – ClO – Hydrogen sulfate Nitrite Hypochlorite 2– SO 3 2– SO 4 2– CO 3 2– Sulfite Sulfate Carbonate 3– PO 4 3 – Phosphate 1+NH 4 + Ammonium

9.1 Naming Ions > 21 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Note the number of oxygen atoms and the endings on each name. You should be able to discern a pattern in the naming convention. -ite -ate SO 3 2−, sulfite SO 4 2–, sulfate NO 2 –, nitriteNO 3 –, nitrate ClO 2 –, chlorite ClO 3 –, chlorate Polyatomic Ions

9.1 Naming Ions > 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The charge is the same on each polyatomic ion in a pair for which there is both an -ite and an -ate ion. The -ite ending indicates one less oxygen atom than the -ate ending. However, the ending does not tell you the actual number of oxygen atoms in the ion. For example, the nitrite ion has two oxygen atoms, and the sulfite ion has three oxygen atoms. Polyatomic Ions

9.1 Naming Ions > 23 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. When the metals in Groups 1A, 2A, and 3A lose electrons, they form cations with positive charges equal to their group number. The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number. Key Concepts

9.1 Naming Ions > 24 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. The charges of the cations of many transition metal ions must be determined from the number of electrons lost. Unlike a monatomic ion, a polyatomic ion is composed of more than one atom. But like a monatomic ion, a polyatomic ion behaves as a unit and carries a charge. Key Concepts

9.1 Naming Ions > 25 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. monatomic ion: a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons Glossary Terms

9.1 Naming Ions > 26 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. An element’s position in the periodic table supplies information on ion formation and bonding tendencies, which is used to write the names and formulas of ions and compounds. BIG IDEA

9.1 Naming Ions > 27 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. END OF 9.1