1. (2.2) IONIC COMPOUNDS (p128-129)
NAMES & FORMULAS

2. Compounds Recall: There are two main types of compounds:
IONIC and MOLECULAR
NaCl, K2SO4 H2O, C6H12O6

3. Ionic Compounds
Ionic compounds are formed by combining a metal and a non-metal.
The positive ion (from the metal) and negative ion (from the non-metal) bond to each other.

4. Ion Symbols and Names
The symbol for an ion is the element symbol with a superscript showing the ionic charge
Metals: The name does not change from the element name unless the element is multivalent (can form different ions).
Na1+ Ca2+ Cu Cu2+
sodium calcium copper I copper II

5. Ion Symbols and Names Non-Metals: The name changes its ending to “ide”
Cl1- O2- S2-
chloride oxide sulfide

6. Naming Ionic Compounds
An ionic compound has a two-part name:
first
second
Metal ion
Non-metal ion
Positive ion
Negative ion
Keeps its name
Changes ending to “ide”

7. Naming Ionic Compounds-Practice
a) sodium & chlorine
b) potassium & oxygen

8. Formulas for Ionic Compounds
What is the chemical formula for the ionic compound formed by magnesium and oxygen?
STEP ONE:
Write the symbol for each element.

9. Formulas for Ionic Compounds
STEP TWO:
add the ionic charges of each

10. Formulas for Ionic Compounds
STEP THREE:
Criss-cross the charges

11. Formulas for Ionic Compounds
STEP FOUR:
Write the formula using subscripts.
STEP FIVE:
Simplify or reduce the ratio, if possible

12. Formulas for Ionic Compounds
Try these: aluminium and oxygen
potassium and nitrogen
copper I and sulfur

13. Answers:
Al2O3
K3N
Cu2S

14. “Weirdos” Multivalent elements can form ions more than one way
There has to be a method of identifying which valence (charge) is used
Pb, Fe, Cu, Sn, Co
to name a few.

15. Multivalent elements Pb2+ 4+ on the periodic table means
lead II (Pb2+) or lead IV (Pb4+)
Fe2+ 3+  iron II or iron III
Cu1+ 2+  copper I or copper II
Sn2+ 4+  tin II or tin IV

16. WEIRDOS
CuCl 
CuCl2 
Fe2O3 

17. HOMEWORK
Worksheet 2.2 (A) compound naming - both sides!