Chapter 4

Compounds and Their Bonds

4.3 Ionic Compounds 4.4 Naming Ionic Formulas

Ionic Compounds



Attraction between + ions and - ions



Electrons go from metals to nonmetals

electron transfer

metal nonmetal ion + ion – Electrons lost = Electrons gain

Formulas of Ionic Compounds

Formulas of ionic compounds are determined from the charges on the ions Na



atoms +

  

F :

  

ions

 

– Na + : F :

  

NaF sodium fluorine sodium fluoride formula Charge balance: 1+ 1 = 0

Writing a Formula

Write the formula for the ionic compound that will form between Ba 2+ and Cl



.

Solution: 1. Balance charge with + and – ions 2. Write the positive ion of metal first, and the negative ion Ba 2+ Cl



Cl



3. Write the number of ions needed as subscripts BaCl 2

Learning Check

Write the correct formula for the compounds containing the following ions: A. Na + , S 2 1) NaS B. Al 3+ , Cl 1) AlCl 3 C. Mg 2+ , N 3 2) Na 2 S 2) AlCl 3) NaS 2 3) Al 3 Cl 1) MgN 2) Mg 2 N 3 3) Mg 3 N 2

A. Na + , S 2 2) Na 2 S B. Al 3+ , Cl 1) AlCl 3 C. Mg 2+ , N 3 3) Mg 3 N 2

Solution

Naming Binary Ionic Compounds



Contain 2 different elements



Name the metal first, then the nonmetal as -ide.



Use name of a metal with a fixed charge Groups 1A, 2A, 3A and Ag, Zn, and Cd Examples: NaCl ZnI 2 Al 2 O 3 sodium chloride zinc iodide aluminum oxide

Learning Check

Complete the names of the following binary compounds: Na 3 N sodium ________________ KBr potassium ________________ Al 2 O 3 MgS aluminum ________________ _________________________

Solution

Complete the names of the following binary compounds: Na 3 N sodium nitride KBr potassium bromide Al 2 O MgS 3 aluminum oxide magnesium sulfide

Transition Metals

Many form 2 or more positive ions 1+ 2+ 1+ or 2+ 2+ or 3+ Ag + Cd 2+ Cu + , Cu 2+ Fe 2+ , Fe 3+ silver cadmium copper(I) ion ion ion iron(II) ion copper (II) ion iron(III) ion Zn 2+ zinc ion

Learning Check

A. The formula for the ionic compound of Na + and O 2 is 1) NaO 2) Na 2 O 3) NaO 2 B. The formula of a compound of aluminum and chlorine is 1) Al 3 Cl 2) AlCl 2 3) AlCl 3 C. The formula of Fe 3+ 1) Fe 3 O 2 and O 2 2) FeO 3 is 3) Fe 2 O 3

Solution

A. The formula for the ionic compound of Na + and O 2 is 2) Na 2 O B. The formula of a compound of aluminum and chlorine is 3) AlCl 3 C. The formula of Fe 3+ and O 2 is 3) Fe 2 O 3

Names of Variable Ions

Use a roman number after the name of a metal that forms two or more ions Transition metals and the metals in groups 4A and 5A FeCl 3 CuCl SnF 4 PbCl 2 Fe 2 S 3 (Fe 3+ ) (Cu + ) (Sn 4+ ) (Pb 2+ ) (Fe 3+ ) iron (III) chloride copper (I) chloride tin (IV) fluoride lead (II) chloride iron (III) sulfide

Learning Check

Complete the names of the following binary compounds with variable metal ions: FeBr Cu 2 O SnCl 4 Fe 2 O 3 CuS 2 iron (_____) bromide copper (_____) oxide ___(_____ ) ______________ ________________________ ________________________

Solution

Complete the names of the following binary compounds with variable metal ions: FeBr Cu 2 O SnCl 4 Fe 2 O 3 CuS 2 iron ( II ) bromide copper ( I ) oxide tin (IV) chloride iron (III) oxide copper (II) sulfide

Learning Check

Name the following compounds: A. CaO 1) calcium oxide 3) calcium (II) oxide 2) calcium(I) oxide B. SnCl 4 1) tin tetrachloride 3) tin(IV) chloride 2) tin(II) chloride C. Co 2 O 3 1) cobalt oxide 3) cobalt trioxide 2) cobalt (III) oxide

Solution

Name the following compounds: A. CaO 1) calcium oxide B. SnCl 4 C.

Co 2 O 3 3) tin(IV) chloride 2) cobalt (III) oxide