1. CLE 3321.31 Investigate chemical bonding.
STANDARD
CLE Investigate chemical bonding.
Analyze ionic and covalent compounds in terms of their formation, names, chemical formulas, percent composition, and molar masses.
Determine the types of chemical bond that occurs in a chemical compound Differentiate between ionic and covalent bond models

2. ESSENTIAL QUESTION
How does a study of valence electrons help to explain most chemical phenomena?

3. OBJECTIVE
Almost 99% of students can draw lewis dot symbols of ions and atoms of different elements in periodic table

4. TASK
Answer questions provided in the end of slide

5. 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

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

7. 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.

8. 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

9. 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

10. 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

11. 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 

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

13. 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