1. After today, you will be able to…
Explain how ionic and covalent bonding occurs
Write dot diagrams for elements in the s and p blocks
Determine the number of valence electrons in a particular atom

2. Unit: Chemical Bonding
Day 1 - Notes
Unit: Chemical Bonding
The Basics of Chemical Bonding

3. Two types of bonding:
Ionic Bonding: Involves a transfer of electrons. One element loses electrons and the other gains electrons.
Covalent Bonding: Involves a sharing of electrons. Atoms will share in order to reach a stable electron configuration.

4. The Octet Rule
Atoms will gain or lose enough electrons to make them isoelectronic with a noble gas. -Except for H and He, there will be 8 electrons in their valence shell

5. Electron Dot Structures
A way to show the number of valence electrons in an atom
Valence electrons must be labeled like this: X 5 2 3 1 6 8 4 7

6. The number of valence electrons can be determined by the group the elements are in – s and p blocks only!
Group # 1 2 13 14 15 16 17 18
Valence E-
E- Dot Strux 1 2 3 4 5 6 7 8

7. Valence electrons determine chemical reactivity – elements in the same group behave the same!1 2 13 14 15 16 17 18
Electron activity
Charge
Group #
Lose/ Gain 4
Lose 1
Lose 2
Lose 3
Gain 3
Gain 2
Gain 1 
+/- 4
Gain 1 X +1 +2 +3 -3 -2 -1 

8. Review: E- Configurations for Ions
Examples:
Mg+2 =
P-3 =
1s2 2s2 2p6 = [Ne]
1s2 2s2 2p6 3s2 3p6 = [Ar]

9. Introduction to Ionic Bonding
An ionic bond forms from the attraction between + and – ions.
An ionic compound is made up of crystals
A crystal consists of a 3D, repeating pattern of alternating + and – ions
Formula unit: the lowest whole number ratio of ions
Ionic compounds have high melting points
Conduct electricity when melted or dissolved
Example: NaCl