1. Ionic Compound Formulas

2. Ions Cation: A positive ion Mg2+, NH4+ Anion: A negative ion
Cl-, SO42-

3. Predicting Ionic Charges
Group 1:
Lose 1 electron to form 1+ ions H+
Li+
Na+ K+

4. Predicting Ionic Charges
Group 2:
Loses 2 electrons to form 2+ ions
Be2+
Mg2+
Ca2+
Sr2+
Ba2+

5. Predicting Ionic Charges
Loses 3
electrons to form
3+ ions
Group 13:
B3+
Al3+
Ga3+

6. Predicting Ionic Charges
Lose 4
electrons or gain
4 electrons?
Group 14:
Neither! Group 13 elements rarely form ions.

7. Predicting Ionic Charges
Nitride
Gains 3
electrons to form
3- ions
Group 15:
Phosphide
P3-
As3-
Arsenide

8. Predicting Ionic Charges
Oxide
Gains 2
electrons to form
2- ions
Group 16:
S2-
Sulfide
Se2-
Selenide

9. Predicting Ionic Charges
Group 17:
Gains 1
electron to form
1- ions
F1-
Fluoride
Cl1-
Chloride
Br1-
Bromide
I1-
Iodide

10. Predicting Ionic Charges
Group 18:
Stable Noble gases do not form ions!

11. Predicting Ionic Charges
Many transition elements
have more than one possible oxidation state.
Groups :
Iron(II) = Fe2+
Iron(III) = Fe3+

12. Predicting Ionic Charges
Some transition elements
have only one possible oxidation state.
Groups :
Zinc = Zn2+
Silver = Ag+

13. Writing Ionic Compound Formulas
Example: Barium nitrate
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Ba
Ba2+
( )
NO3-
NO3 2
Not balanced!

14. Writing Ionic Compound Formulas
Example: Ammonium sulfate
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
( )
NH4+
SO42- 2
Not balanced!

15. Summary of Steps:

16. Writing Ionic Compound Formulas
Example: Iron(III) chloride
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Fe3+
Cl- 3
Not balanced!

17. Writing Ionic Compound Formulas
Example: Aluminum sulfide
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
Al3+
S2- 2 3
Not balanced!

18. Writing Ionic Compound Formulas
Example: Magnesium carbonate
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
Mg2+
CO32-
They are balanced!

19. Writing Ionic Compound Formulas
Example: Zinc hydroxide
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
3. Balance charges , if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion.
( )
Zn2+
OH- 2
Not balanced!

20. Writing Ionic Compound Formulas
Example: Aluminum phosphate
1. Write the formulas for the cation and anion, including CHARGES!
2. Check to see if charges are balanced.
Al3+
PO43-
They ARE balanced!

21. Naming Ionic Compounds
Cation first, then anion
Monatomic cation = name of the element
Ca2+ = calcium ion
Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

22. Naming Ionic Compounds (continued)
Metals with multiple oxidation states
some metal forms more than one cation
use Roman numeral in name
PbCl2
Pb2+ is cation
PbCl2 = lead(II) chloride