1. Chapter 2 The Material World
Molecules
Chapter 2
The Material World

2. Forming Ionic Compounds (Simple)

3. What are ionic compounds?
Ionic compounds are compounds formed between a metal and a non-metal
Metals lose electrons
Non-metals gain electrons 2+ 2- Mg S

5. NaCl Na Cl Na Cl - + Examples: Ionic Bonds
Draw the Lewis dot diagram to show the bond between sodium and chlorine. Na Cl
NaCl - + Na Cl

6. Li2O Li O Li Li O + Examples: Ionic Bonds 2-
Draw the Lewis dot diagram to show the bond between Lithium and Oxygen. Li O Li
Li2O 2- + Li O

7. Mg N N N Mg3N2 Mg Mg Mg 2+ Examples: Ionic Bonds 3-
3. Draw the Lewis dot diagram to show the bond between magnesium and nitrogen. N Mg Mg Mg N
Mg3N2 2+ 3- Mg N

8. Mg+2 Cross Over Method Mg 12p+ +12 10e- -10 +2 2 valance e-
Wants to lose 2 e- to achieve full octet
If Mg loses 2 e-  now has 12p+ and 10e-
Mg+2
12p+
10e-
+12
-10 +2

9. F-1 Cross Over Method F 9p+ +9 10e- -10 -1 7 valance e-
Wants to gain 1e- to achieve full octet
If F gains 1 e-  now has 9p+ and 10e-
F-1
9p+
10e- +9
-10 -1

10. Mg+2
F-1
Mg1F2
Do not have to show “1”

11. +2 F -1 Mg 1 2
Do not have to show “1”
MgF2

12. Examples:
Al+3
S-2
Al2S3

13. Ca+2
O-2
Ca2O2
Ca1O1