© Copyright Pearson Prentice Hall Slide 1 of 29 Naming and Writing Formulas for Ionic Compounds A recipe is a formula for the sauce—a complete list of ingredients and their proportions. Chemistry also uses formulas. Once you know the rules, you can write the formula for any chemical compound. 9.2

Slide 2 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Binary Ionic Compounds How are the names of binary ionic compounds determined? How do you write the formulas for binary ionic compounds? 9.2

Slide 3 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Binary Ionic Compounds These masks are made of an ionic compound with the common name gypsum. This name does not tell you anything about the chemical composition of the compound, though. 9.2

Slide 4 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Binary Ionic Compounds Naming Binary Ionic Compounds A binary compound is composed of two elements and can be either ionic or molecular. To name any binary ionic compound, place the cation name first, followed by the anion name. 9.2

Slide 5 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Binary Ionic Compounds Hematite, a common ore of iron, contains iron (III) oxide. The balanced formula is Fe 2 O

Slide 6 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Binary Ionic Compounds Writing Formulas for Binary Ionic Compounds Write the symbol of the cation and then the anion. Add whatever subscripts are needed to balance the charges. 9.2

© Copyright Pearson Prentice Hall Slide 7 of 29 Conceptual Problem

© Copyright Pearson Prentice Hall Slide 8 of 29 a) CuS Cu 2+ and S 2- charges cancel each other out so final formula is indicative of needing 1 each of the cation and anion to form a neutral compound overall. b) K 3 N Same thing here. We need 3 potassiums to cancel out the 3 negative charge of nitride.

© Copyright Pearson Prentice Hall Slide 9 of 29 Practice Problems Sample Problems For Conceptual Problem 9.2 Problem Solving 9.11 Solve Problem 11 with the help of an interactive guided tutorial. for Conceptual Problem 9.2

© Copyright Pearson Prentice Hall Slide 10 of 29 > Naming and Writing Formulas for Ionic Compounds Compounds With Polyatomic Ions Compounds with Polyatomic Ions How do you write the formulas and names of compounds containing polyatomic ions? 9.2

© Copyright Pearson Prentice Hall Slide 11 of 29 > Naming and Writing Formulas for Ionic Compounds Compounds With Polyatomic Ions Write the symbol for the cation followed by the formula for the polyatomic ion and balance the charges. 9.2

Slide 12 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Compounds With Polyatomic Ions For example, calcium nitrate is composed of a calcium cation (Ca 2+ ) and a polyatomic nitrate anion (NO 3– ). In calcium nitrate, two nitrate anions, each with a 1– charge, are needed to balance the 2+ charge of each calcium cation. The formula for calcium nitrate is Ca(NO 3 )

© Copyright Pearson Prentice Hall Slide 13 of 29 Conceptual Problem

© Copyright Pearson Prentice Hall Slide 14 of 29 Practice Problems Practice Problems For Conceptual Problem 9.3 Problem-Solving 9.12 Solve Problem 12 with the help of an interactive guided tutorial. for Conceptual Problem 9.3

Slide 15 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Compounds With Polyatomic Ions Naming Compounds with Polyatomic Ions To name a compound containing a polyatomic ion, state the cation first and then the anion, just as you did in naming binary ionic compounds. 9.2

Slide 16 of 29 © Copyright Pearson Prentice Hall > Naming and Writing Formulas for Ionic Compounds Compounds With Polyatomic Ions Sodium hypochlorite (NaClO) is used as a disinfectant for swimming pools. The metallic cation in this compound is sodium (Na + ) so the polyatomic ion must be ClO –. 9.2

© Copyright Pearson Prentice Hall Slide 17 of Section Quiz 1.The correct name for CrCl 3 is a.chromium chlorine. b.chromium(III) chloride. c.monochromium trichloride. d.chromium(III) trichloride.

© Copyright Pearson Prentice Hall Slide 18 of 29 2.What is the correct formula for strontium nitride? a.Sr 3 N 2 b.SrN 2 c.Sr 2 N 3 d.Sr 3 N 9.2 Section Quiz

© Copyright Pearson Prentice Hall Slide 19 of 29 3.Which one of the following compounds is named correctly? a.sodium chlorite, NaClO b.potassium nitrate, KNO 2 c.sodium acetate, NaC 2 H 3 O 2 d.lithium sulfate, Li 2 SO Section Quiz