writing ionic compounds in chemistry.pptx

writing ionic compounds

1. Aim: How do we write the chemical formula of an ionic compound given the chemical name 1

2. Binary Compound Binary Compounds are composed of two elements bonded together One METAL Ion and One NONMETAL Ion for Ionic Compound Metal atoms lose electrons to form positively charged ions. Some metals form one ion, while others (usually transition metals) can form multiple ions. Nonmetal atoms gain electrons to form negatively charged ions. Nonmetals form only one negative ion. General naming format for binary ionic compounds “ metal ion name + nonmetal ion name ”

3. Naming Ionic compounds with metals that have only one oxidation state 3

4. 4 Names of Some Common Ions Naming metal ions with one oxidation state: Element name + ion Naming nonmetal ions: element stem name + “ ide ” + ion

5. 5 Formula Ions Name cation anion NaCl Na + Cl - sodium chloride K 2 S K + S 2- potassium sulfide MgO Mg 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

6. 6 Learning Check Chemical Formula Positive Ion (metal ion) Negative Ion (nonmetal ion) Does the metal form one ion? Mathematic-ally check if compound is neutral Chemical Name CaO KBr Al 2 O 3 MgCl 2

7. 7 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.

8. 8 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. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings Lead Pb 2+ lead(II) Pb 4+ lead(IV)

9. 9 Naming Variable Charge Metals Transition metals with two or more different ions use a Roman numeral after the name of the metal to indicate ionic charge.

10. 10 Naming Ionic Compounds with Variable Charge Metals

11. 11 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 (-1) = 0 Fe ion = 2+ 2. 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

12. 12 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 3+ 2. 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

13. 13 Learning Check Chemical Formula Positive Ion (metal ion) Negative Ion ( nonmetal ion) Does the metal form one ion? Mathematic-ally check if compound is neutral Chemical Name MgCl 2 KCl AgF FeO Pb I 4

14. 1 . Determine if the metal is a transition metal. 2. If Transition Metal, Determine the proper oxidation number to use. (Use nonmetal to help you determine ) 3. Write down the name of the metal. (use roman numerals to show oxidation state for transition metals ) 4. Write the name of the non-metal, changing the ending to ide Ex: Oxide, Fluoride, Bromide, Chloride, Nitride Summary Steps to naming Binary Ionic Compounds 14