1. Ionic Compounds Due Today: “Formation of Ions” worksheet
Objective: Students will be able to write balanced chemical formulas for ionic compounds and name these compounds according to IUPAC system of nomenclature
Agenda:
Warm-up/Binder Set Up
Lecture/notes ionic compounds
Ionic Compounds Activity
Exit Ticket
Homework
Ionic Compounds Activity if not completed in class. Due 1/14
Warm-up – Give the name and ionic symbol for the ions that the following elements will form. Label each ion as cation or anion.
Calcium
Strontium
Fluorine

2. Formation of Ionic Compounds
Ionic Compounds are composed of cations (metals) and anions (non-metals)
Although they are composed of ions, ionic compounds are electrically neutral (meaning that the positive charge equals the negative charge)

3. Ionic Bonds
An ionic bond is formed when the positive charge of a cation and the negative charge of an anion attract one another

4. Properties of Ionic Compounds
Most are crystalline solids at room temperature
Generally have high melting points
Conduct electricity when dissolved in solution. When ionic compounds dissolve in water they break down into their ions.

5. Formula Units
Ionic Compounds exist as collection of negative and positive charge arranged in repeated patterns.
The smallest whole number ratio that exists between the cations and anions that form an ionic compound.
Example:
Sodium Chloride (NaCl) is Na+ and Cl- ionically bonded. Ions are distributed in a 1:1 ratio

6. Chemical Formula
The chemical formula shows the kinds and the number of atoms in a substance
Examples
Sodium and Chlorine = NaCl
Aluminum and Bromine = AlBr3
Magnesium and Oxygen = MgO

7. Writing Binary Ionic Compounds
The cation (metal) with the correct charge (oxidation number) is written first
The anion (nonmetal) with the correct charge (oxidation number) is written second

8. How to Write Ionic Formulas
Criss-Cross the charges from the superscripts to subscripts using the absolute values (do not include + or - signs)
Example

9. How to Write Ionic Formulas
Check to make sure the subscripts are in the lowest possible ratio to one another  simplify subscripts if needed.
Example

10. Practice Write the Ionic Formula for Barium and Chlorine
Step 1: Write the cation with charge first and anion with charge second
Ba2+ Cl-
Step 2 Criss-cross the superscripts
Why is there no subscript for Ba?
Step 3: Simplify subscripts if needed.

11. Polyatomic Ions
An ion in which two or more atoms are bonded covalently

12. It is important to know the correct charges of polyatomic ions so that you can write the correct formula
When a formula contains multiple polyatomics, you must “keep it together” by putting it in parenthesis.
Example: Ca3(PO4)2 – calcium phosphate
The charge must still equal zero!

13. Practice with polyatomic ions
Write the formula for
Aluminum Hydroxide
Barium sulfate
Sodium Phosphate

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

15. Charges of Representative Elements
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16. Names of Some Common Ions

17. Learning Check Complete the names of the following ions: Ba2+ Al3+ K+
_________ __________ _________
N3 O2 F
_________ __________ _________
P3 S2 Cl

18. Solution Ba2+ Al3+ K+ barium aluminum potassium N3 O2 F
nitride oxide fluoride
P3 S2 Cl
phosphide sulfide chloride

19. Examples of Ionic Compounds with Two Elements
Formula Ions Name
cation anion
NaCl Na+ Cl- sodium chloride
K2S K S2- potassium sulfide
MgO Mg2+ O2- magnesium oxide
CaI2 Ca2+ I- calcium iodide
Al2O3 Al O2- aluminum oxide

20. Learning Check Write the names of the following compounds:
1) CaO ___________
2) KBr ___________
3) Al2O3 ___________
4) MgCl2 ___________

21. Solution Write the names of the following compounds:
1) CaO calcium oxide
2) KBr potassium bromide
3) Al2O3 aluminum oxide
4) MgCl2 magnesium chloride

22. Learning Check
Write the formulas and names for compounds of the following ions:
Br− S2− N3−
Na+
Al3+

23. Solution Na+ Al3+ NaBr sodium bromide Na2S sodium sulfide Na3N
Br− S2− N3−
Na+
Al3+
NaBr
sodium bromide
Na2S
sodium sulfide
Na3N
sodium nitride
AlBr3
aluminum bromide
Al2S3
aluminum sulfide
AlN
aluminum nitride

24. Transition Metals Form Positive Ions
Most transition metals and Group 4 (14) metals form 2 or more positive ions. However, Zn2+, Ag+, and Cd2+ form only one ion.

25. 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.

26. Naming Ionic Compounds with Variable Charge Metals

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

28. Naming FeCl2 To name FeCl2:
1. Determine the charge of the cation using the charge
of the anion (Cl-).
Fe ion Cl- = Fe ion = 0
Fe ion = 2+
2. Name the cation by the element name and add a
Roman numeral in parentheses to show its charge.
Fe2+ = iron(II)
3. Write the anion with an ide ending.
FeCl2 = iron(II) chloride

29. Naming Cr2O3
To name Cr2O3:
1. Determine the charge of cation from the anion (O2-).
2 Cr ions O2- = 0
2 Cr ions (2-) = 0
2 Cr ions = 0
2 Cr ions = 6+
Cr ion = 3+ = Cr3+
2. Name the cation by the element name and add a
Roman numeral in parentheses to show its charge.
Cr3+ = chromium(III)
3. Write the anion with an ide ending.
chromium(III) oxide = Cr2O3

30. Learning Check Select the correct name for each. A. Fe2S3
1) iron sulfide
2) iron(II) sulfide
3) iron(III) sulfide
B. CuO
1) copper oxide
2) copper(I) oxide
3) copper(II) oxide

31. Solution Select the correct name for each. A. Fe2S3
3) iron (III) sulfide Fe3+ S2-
B. CuO
3) copper (II) oxide Cu2+ O2-

32. Guide to Writing Formulas from the Name
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33. Writing Formulas Write a formula for potassium sulfide.
1. Identify the cation and anion.
potassium = K+
sulfide = S2−
2. Balance the charges.
K S2− K+
2(1+) + 2(1-) = 0
3. 2 K+ and 1 S2− = K2S

34. Writing Formulas Write a formula for iron(III) chloride.
1. Identify the cation and anion.
iron (III) = Fe3+ (III = charge of 3+)
chloride = Cl−
2. Balance the charges.
Fe Cl−
Cl− = (3+) + 3(1-) = 0
Cl−
3. 1 Fe3+ and 3 Cl− = FeCl3

35. Learning Check What is the correct formula for each of the following?
A. Copper(I) nitride
1) CuN 2) CuN3 3) Cu3N
B. Lead(IV) oxide
1) PbO2 2) PbO 3) Pb2O4

36. Solution The correct formula is A. Copper(I) nitride
3) Cu3N Need 3 Cu+ and N3-
B. Lead(IV) oxide
1) PbO2 Need Pb4+ and 2 O2-