1. Introduction to Chemical Bonding Table of Contents Lecture/Lab/Activity Date Pg# 22. The Periodic Table9/24/10 47 23. Periodic Def & Trends9/27/10 49 24. Electron config practice10/4/10 51 25. Ions and Oxidation Numbers10/5/10 53 26. Lewis Dot Diagram10/6/10 54 27. Intro to Chemical Bonding10/7/10 57 Objective: The student will record lecture notes on the Introduction to Chemical Bonding to make a comparison of the different types of Chemical bonds & bond polarity. Agenda: Introduction to Chemical Bonding – Lecture

2. Vocabulary Chemical Bond attractive force between atoms or ions that binds them together as a unit bonds form in order to… decrease potential energy (PE) increase stability Chemical Bond attractive force between atoms or ions that binds them together as a unit bonds form in order to… decrease potential energy (PE) increase stability

3. Vocabulary CHEMICAL FORMULA Molecular Formula Unit IONICCOVALENT CO 2 NaCl

4. Vocabulary COMPOUND Ternary Compound Binary Compound 2 elements more than 2 elements NaNO 3 NaCl

5. Vocabulary ION Polyatomic Ion Monatomic Ion 1 atom 2 or more atoms NO 3 - Na +

6. Types of Chemical Bonds IONICCOVALENT Bond Formation Type of Structure Solubility in Water Other Properties high yes (solution or liquid) yes low no usually not Melting Point Physical State solidliquid or gas odorous Electrical Conductivity crystal lattice e - are transferred from metal to nonmetal true molecules e- are shared between two nonmetals

7. Types of Chemical Bonds METALLIC Bond Formation Type of Structure Solubility in Water Electrical Conductivity Other Properties Melting Point Physical State e - are delocalized among metal atoms very high yes (any form) no malleable, ductile, lustrous solid “electron sea”

8. Bond Polarity Most bonds are a blend of ionic and covalent characteristics. Difference in electronegativity determines bond type.

9. Bond Polarity Electronegativity Attraction an atom has for a shared pair of electrons. higher e - neg atom   - lower e - neg atom   +

10. Bond Polarity Electronegativity Trend Increases up and to the right.

11. Nonpolar Covalent Bond e - are shared equally symmetrical e - density usually identical atoms Bond Polarity

12. ++ -- Polar Covalent Bond e - are shared unequally asymmetrical e - density results in partial charges (dipole)

13. zNonpolar zPolar zIonic View Bonding Animations.Bonding Animations Bond Polarity

14. Examples: Cl 2 HCl NaCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9 Polar 3.0-0.9=2.1 Ionic

15. Least electronegative element = Cs – 0.7 Most electronegative element = F – 4.0 Ionic = EN > 1.7 Polar-covalent = EN 0.3 > 1.7 Nonpolar-covalent = EN < 0.3 Least electronegative element = Cs – 0.7 Most electronegative element = F – 4.0 Ionic = EN > 1.7 Polar-covalent = EN 0.3 > 1.7 Nonpolar-covalent = EN < 0.3 Bond Polarity