Naming and Writing Ionic Formulas

Naming Ionic Compounds with Two Elements To name a compound that contains two elements, identify the cation and anion. mame the cation first followed by the name of the anion.

Charges of Representative Elements

Names of Some Common Ions

Complete the names of the following ions. Ba 2+ Al 3+ K + _________ __________ _________ N 3  O 2  F  _________ __________ _________ P 3  S 2  Cl  _________ __________ _________ Learning Check

Ba 2+ Al 3+ K + barium aluminum potassium N 3  O 2  F  nitride oxide fluoride P 3  S 2  Cl  phosphide sulfide chloride Solution

Formula IonsName cation anion NaClNa + Cl - sodium chloride K 2 SK + S 2- potassium sulfide MgOMg 2+ O 2- magnesium oxide CaI 2 Ca 2+ I - calcium iodide Al 2 O 3 Al 3+ O 2- aluminum oxide Examples of Ionic Compounds with Two Elements

Write the names of the following compounds. 1) CaO___________ 2) KBr___________ 3) Al 2 O 3 ___________ 4) MgCl 2 ___________ Learning Check

Write the names of the following compounds: 1)CaOcalcium oxide 2)KBrpotassium bromide 3)Al 2 O 3 aluminum oxide 4)MgCl 2 magnesium chloride Solution

Learning Check Write the formulas and names for compounds of the following ions: Br − S 2− N 3− Na + Al 3+

Solution Br − S 2− N 3− Na + Al 3+ NaBr sodium bromide Na 2 S sodium sulfide Na 3 N sodium nitride AlBr 3 aluminum bromide Al 2 S 3 aluminum sulfide AlN aluminum nitride

Transition Metals form Positive Ions Most transition metals and Group 4(14) metals form 2 or more positive ions. Zn 2+, Ag +, and Cd 2+ form only one ion.

Metals that form more than One Cation The name of metals with two or more positive ions (cations) use a Roman numeral to identify ionic charge. Lead Pb 2+ lead(II) Pb 4+ lead(IV)

Naming Ionic Compounds with Variable Charge Metals

Naming Variable Charge Metals Transition metals with two different ions use a Roman numeral after the name of the metal to indicate ionic charge.

Naming FeCl 2 To name FeCl 2 1. Determine the charge of the cation using the charge of the anion (Cl - ). Fe ion + 2 Cl - = Fe ion + 2- = 0 Fe ion = Name the cation by the element name and add a Roman numeral in parenthesis to show its charge. Fe 2+ = iron(II) 3. Write the anion with an ide ending. FeCl 2 = iron(II) chloride

Naming Cr 2 O 3 To name Cr 2 O 3 1. Determine the charge of cation from the anion (O 2- ). 2 Cr ions + 3 O 2- = 0 2 Cr ions + 3(2-) = 0 2 Cr ions - 6 = 0 2 Cr ions = +6 Cr ion = 3+ = Cr Name the cation by the element name and add a Roman numeral in parenthesis to show its charge. Cr 3+ = chromium(III) 3. Write the anion with an ide ending. chromium(III) oxide = Cr 2 O 3

Learning Check Select the correct name for each. A. Fe 2 S 3 1) iron sulfide 2) iron(II) sulfide 3) iron(III) sulfide B. CuO 1) copper oxide 2) copper(I) oxide 3) copper(II) oxide

Solution Select the correct name for each. A. Fe 2 S 3 3) iron (III) sulfide Fe 3+ S 2- B. CuO 3) copper (II) oxide Cu 2+ O 2-

Guide to Writing Formulas from the Name

Writing Formulas Write a formula for potassium sulfide. 1. Identify the cation and anion. potassium = K + sulfide = S 2− 2. Balance the charges. K + S 2− K + 2(1+) + 2(1-) = K + and 1 S 2− = K 2 S

Writing Formulas Write a formula for iron(III) chloride. 1. Identify the cation and anion. iron (III) = Fe 3+ (III = charge of 3+) chloride = Cl − 2. Balance the charges. Fe 3+ Cl − Cl − = (3+) + 3(1-) = 0 Cl − 3. 1 Fe 3+ and 3 Cl − = FeCl 3