1. Ionic Compounds: Names and Formulas
SNC2D

2. Counting Ions Sodium chloride or NaCl
contains 1 sodium ion and 1 chloride ion.
(Lewis dot diagrams)

3. Counting Ions
However, different ions may form compounds in different ratios.
For example, calcium chloride or CaCl2
contains 1 calcium ion and 2 chloride ions.
(Subscripts are added to the symbols in a formula if there is more than one of that type of atom.)

4. Counting Ions: Practice
FeCl3
Na2O
CaO
Fe2O3
NaClO3
Na2CO3
Ca(ClO3)2

5. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O
CaO
Fe2O3
NaClO3
Na2CO3
Ca(ClO3)2

6. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO
Fe2O3
NaClO3
Na2CO3
Ca(ClO3)2

7. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO contains 1 calcium ion and 1 oxide ion
Fe2O3
NaClO3
Na2CO3
Ca(ClO3)2

8. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO contains 1 calcium ion and 1 oxide ion
Fe2O3 contains 2 iron ions and 3 oxide ions
NaClO3
Na2CO3
Ca(ClO3)2

9. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO contains 1 calcium ion and 1 oxide ion
Fe2O3 contains 2 iron ions and 3 oxide ions
NaClO3 contains 1 sodium ion and 1 chlorate ion
Na2CO3
Ca(ClO3)2

10. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO contains 1 calcium ion and 1 oxide ion
Fe2O3 contains 2 iron ions and 3 oxide ions
NaClO3 contains 1 sodium ion and 1 chlorate ion
Na2CO3 contains 2 sodium ions and 1 carbonate ion
Ca(ClO3)2

11. Counting Ions: Practice
FeCl3 contains 1 iron ion and 3 chloride ions
Na2O contains 2 sodium ions and 1 oxide ion
CaO contains 1 calcium ion and 1 oxide ion
Fe2O3 contains 2 iron ions and 3 oxide ions
NaClO3 contains 1 sodium ion and 1 chlorate ion
Na2CO3 contains 2 sodium ions and 1 carbonate ion
Ca(ClO3)2 contains 1 calcium ion and 2 chlorate ions

12. Why These Ratios?
It is the valence electrons that determine how these ions combine.
For example, calcium had 2 valence electrons to lose and each chlorine only wants 1. So calcium has to find 2 chlorines.

13. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1-
Li1+ and P3-
Ca2+ and O2-
Al3+ and OH1-
K1+ and SO42-

14. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1- MgBr2
Li1+ and P3-
Ca2+ and O2-
Al3+ and OH1-
K1+ and SO42-

15. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1- MgBr2
Li1+ and P3- Li3P
Ca2+ and O2-
Al3+ and OH1-
K1+ and SO42-

16. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1- MgBr2
Li1+ and P3- Li3P
Ca2+ and O2- CaO
Al3+ and OH1-
K1+ and SO42-

17. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1- MgBr2
Li1+ and P3- Li3P
Ca2+ and O2- CaO
Al3+ and OH1- Al(OH)3
K1+ and SO42-

18. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Mg2+ and Br1- MgBr2
Li1+ and P3- Li3P
Ca2+ and O2- CaO
Al3+ and OH1- Al(OH)3
K1+ and SO42- K2SO4

19. Ratio Practice
Use diagrams to determine how the following combine to form compounds:
Al3+ and O2- Al2O3
Notice that the quick method of determining the formula is to criss-cross the valences:

20. Criss-cross
But the ratio between the ions must be reduced to lowest terms (and 1s are not written).
E.g. Pb4+ and O2- becomes
? not Pb2O4

21. Criss-cross
But the ratio between the ions must be reduced to lowest terms (and 1s are not written).
E.g. Pb4+ and O2- becomes
PbO2 not Pb2O4
Please complete “More Formula Practice.”

22. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
NaCl
CaCl2
Li2O

23. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
NaCl is sodium chloride
CaCl2
Li2O

24. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
NaCl is sodium chloride
CaCl2 is calcium chloride
Li2O

25. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
NaCl is sodium chloride
CaCl2 is calcium chloride
Li2O is lithium oxide

26. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
KOH
Mg(ClO3)2
NH4F

27. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
KOH is potassium hydroxide
Mg(ClO3)2
NH4F

28. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
KOH is potassium hydroxide
Mg(ClO3)2 is magnesium chlorate
NH4F

29. Ionic Compounds: Names
The name of an ionic compound is simply the name of the positive ion followed by the name of the negative ion, e.g.:
KOH is potassium hydroxide
Mg(ClO3)2 is magnesium chlorate
NH4F is ammonium fluoride

30. Names with Multivalent Ions
The only tricky ones to name are those that contain multivalent ions. It is necessary to look at how the ions have combined to figure out the valence of the multivalent ion.
FeO must be
Fe2O3 must be

31. Names with Multivalent Ions
The only tricky ones to name are those that contain multivalent ions. It is necessary to look at how the ions have combined to figure out the valence of the multivalent ion.
FeO must be iron (II) oxide
(because oxide is O2-)
Fe2O3 must be

32. Names with Multivalent Ions
The only tricky ones to name are those that contain multivalent ions. It is necessary to look at how the ions have combined to figure out the valence of the multivalent ion.
FeO must be iron (II) oxide
(because oxide is O2- and the ratio is 1:1)
Fe2O3 must be iron (III) oxide

33. Names with Multivalent Ions
Try it with copper:
CuCl2
CuSO4
Cu2O

34. Names with Multivalent Ions
Try it with copper:
CuCl2 copper (II) chloride
CuSO4
Cu2O

35. Names with Multivalent Ions
Try it with copper:
CuCl2 copper (II) chloride
CuSO4 copper (II) sulphate
Cu2O

36. Names with Multivalent Ions
Try it with copper:
CuCl2 copper (II) chloride
CuSO4 copper (II) sulphate
Cu2O copper (I) oxide