1. Names and Formulas of Ionic Compounds
3.2
Names and Formulas of Ionic Compounds

2. Objectives By the end of the lesson you should be able to:
Describe simple and complex ions
Name and write formulas for all types of ionic compounds

3. WARM UP! Counting Atoms Practice
Formula
# of Atoms
NaCl
Mg(OH)2
HNO3
(NH4)2O
H2SO4
NH4NO3 2 5 5 11 7 9

4. Complex and Simple Ions
Simple Ions: one atom with a charge
H S-2 Cu Cu+2
Complex Ions: more than one atom with an overall charge
Called polyatomic ions
Listed on pg 92 in your textbook
SO4-2 NO NH4+1

5. Remember… ALL ELEMENTS WANT TO HAVE FULL OUTER SHELLS!
The combining capacity (AKA: ion charge) tells you how many electrons have been lost/gained to get a full outer shell

6. Names and Formulas
Naming compounds: involves writing out the entire name for each element in the compound
Compound and symbols given  make name!
Formulas: involve using symbols of each element to make the compound
Name given  make compound with symbols

7. Ionic Compounds
Always involve a positive charge (metal) and a negative charge (non-metal)
Electrons are always transferred from the positive to the negative
Create ions because losing and gaining electrons (charges result)

8. Rules for Naming Ionic Compounds
Metal always first; name never changes
Non-metal second; ending becomes “ide”
EX:
NaCl = sodium chloride
MgF2 = magnesium fluoride
Al2O3 = aluminum oxide

9. Your Turn!
Practice Problems pg. 86 (check your answers on page 509!)

10. Chemical Formulas of Ionic Compounds
Formulas contain symbols to identify each ion in an ionic compound, as well as the relative numbers of ions in the compound.
Example: NaCl – 1 sodium:1chlorine
CaF2 – 1 calcium:2 fluorine atoms
Note: Relative numbers of each ion is a subscript to the right of the symbol

11. Ionic Compound Formulas
Get symbol and charge
Charges are the same skip to step 2
If charges are different “swap and drop”
Combine

12. Ionic Compound Formulas
Calcium chloride (write the symbols)
Ca Cl (superscript combining capacities)
Ca 2+ Cl 1-
Ca 2+ Cl 1-(drop the +/- signs and cross combining capacities)
5. CaCl2

13. Your Turn!
Practice Problems pg. 87 (check your answers on page 509!)

14. Multivalent Ionic Compounds
Multivalent = more than one possible combining capacity (ion charge)
Found in the Transition Metals section
Same naming as Ionic Compounds
BUT use a roman numeral to show which combining capacity is used
I II III IV V VI VII VIII

15. Multivalent Ionic Compound Formulas (Roman Numeral given)
Get symbol and possible charges
Choose appropriate ion (from Roman Numeral)
Charges are the same skip to step 2
If charges are different “swap and drop”
Combine
Reduce to lowest common ratio if need
Ex. Iron (III) oxide =
Iron (II) oxide =
Lead (IV) oxide =
Fe2O3
FeO
PbO2

16. Your Turn!
Practice Problems pg. 89 (every 2nd question: a, c, e, g, i, k, m, o)
(check your answers on page 509!)

17. Compounds Containing Multivalent Metals
Notice that some metallic elements have more than one possible ion charge.
We need to use Roman Numerals to indicate which combining capacity is used.
E.g. Copper (II) chloride  Cu +2
E.g. Copper (I) chloride  Cu +1

18. Naming Multivalent Ionic Compounds (no Roman Numeral given)
Get possible charges
Determine which charge will give the correct formula (reverse swap and drop)
Write the name same as you did with Ionic Compounds
Add the appropriate Roman Numeral between the metal and non-metal

19. Naming: Multivalent Metal
Use the Roman Numeral equal to the ionic charge to indicate which combining capacity was used
E.g. CuCl2
Cu1+ or Cu2+ ?
Copper (II) chloride
E.g. Fe2O3
Fe3+ or Fe2+ ?
Iron (III) oxide
You need to reverse swap and drop to find combining capacities (ion charges).

20. Your Turn!
Practice Problems pg. 90 (every 2nd question: a, c, e, g, i, k, m, o)
Check answers on page 509!

21. Naming Polyatomic Ionic Compounds
Usually seen in more complicated compounds
List of Polyatomic Ions is found in your textbook on pg.92 and on the back of your periodic table during tests!
Look up both names
Check for multivalent charges and insert Roman Numerals if need be
Combine
Ex. NH4OH
FeCrO4
Ammonium hydroxide
Iron (II) chromate

22. Polyatomic Ionic Compound Formulas
Get symbol and possible charges
If same skip to step 2
If different “swap and drop”
Combine – use brackets if need be for polyatomic ions ONLY

23. Polyatomic Ionic Compound Formulas
E.g. Ammonium sulfide
Ammonium = NH (1+ is the ion charge)
(given on the back of the Periodic Table)
When NH4 1+ and S-2 combine, the NH4 polyatomic ion group stays together
You need to put brackets around NH4 so you can separate the digits then swap and drop.
So, (NH4) 1+ S 2-
(NH4)2 S

24. Polyatomic Ionic Compound Formulas
Ex. Ammonium hydroxide =
Ammonium carbonate =
NH4OH
(NH4)2CO3

25. Your Turn!
Practice Problems pg. 91 (every 2nd question: a, c, e, g, i)
Check answers on page 509!
Worktime!
Workbook p. 47 – 49
Textbook p. 95 for extra practice if you need!
Names & Formulas quiz next day!