1. Chapter 6.1 CHEMICAL BONDING

2. Objectives: Define chemical bond Explain why most atoms form chemical bonds Describe ionic and covalent bonding Explain why most chemical bonding is neither purely ionic nor purely covalent Classify bonding type according to electronegativity differences

3. Chemical Bonding In nature, most atoms are joined to others by chemical bonds

5. Nature – favors a minimized potential energy

6. Most atoms are less stable by themselves than when they are combined

8. Covalent Bond Examples

10. Usually somewhere in between, depending on how strongly each atom attracts electrons. (Electronegativity)

11. Determine by calculating difference in electronegativityFor example: Cs – 0.7 F – 4.0 So, 4.0 – 0.7 = 3.3 Use scale to determine

12. Difference in Electronegativity 1. If the electronegativity difference (usually called DEN) is less than 0.3, then the bond is nonpolar covalent.2. If the DEN is between 0.3 and 1.6, the bond is considered polar covalent3. If the DEN is greater than 1.7, then the bond is ionic.

13. Chart of polarities

15. balanced distribution of electric charge

16. Polar-covalent bond : bonding electrons are shared unequally by the atoms