2. Ionic Bonding  Metal and Nonmetal  Electron transfer between atoms, ELECTRON STEALING  ION formation (cation, anion)  Opposite charges attract and hold atoms together  Ions attracted to neighbords, not just one ion  Ionic Bonds—  Attractive electrostatic forces connecting cations and anions

3. Ionic Bonding--Crystals  Interactions among ions lead to a patterned arrangement of cations and anions that repeats, CRYSTAL  What is a diamond really? (diamond lattice)

4. Ionic Bonds BBetween atoms of metals and nonmetals with very different electronegativity HHuge difference in electronegativity EElectronegativity value > 1.7 FForm between elements located on opposite sides of the periodic table

5. Ionic Bonds (cont.)  Conductors  High melting point.  Water soluble  Crystallize (form crystals)  Examples; NaCl, CaCl 2, K 2 O

6. Ionic Bonds: One Big Greedy Thief Dog!

7. Example 1: NaCl

8. Example 2: CaO

9. Example 3: K 2 O You Try !

10. Covalent Bonding  ELECTRON SHARING between 2 atoms (nonmetals)  Formation of MOLECULES  Small difference in electronegativity  Bonding pairs—  Electron pairs shared between atoms  Nonbonding/lone pairs—  Unshared electrons, “lone wolves”  Only reside around one atom

11. Covalent Bonding continued….  Between nonmetallic elements of similar electronegativity.  Small electronegativity difference <1.7  Formed between elements on the same side of the periodic table.

12. Example 1: Cl 2

13. Example 2: H 2 O

14. Multiple Bonds  Single bonds—  1 electron pair shared between atoms  Double bonds—  2 electron pairs shared between atoms  Triple bonds—  3 electron pairs shared between atoms

15. Example 1: CO 2

16. Example 2: N 2

18. What is polarity?  Focus on covalent bonds  Contributes to the properties of chemical compounds  Based on electronegativity difference between atoms within chemical bonds

19. Electronegativity and Bond Polarity  Covalent Bond Polar Covalent Ionic Bond (0—0.5)(0.5—1.9) (1.9—3.5)

20. Chose your polarity 1) Nonpolar Covalent  small to same electronegativity difference  Occurs among same or similar atoms bonded together  EQUAL sharing of electrons, equal distribution of electron density 2) Polar Covalent  difference in electronegativity  Most electronegative atom pulls electrons towards it  UNEQUAL sharing of electrons, electron density displaced toward electronegative atom

21. Polar Covalent Bonds

23. Example 1:  Arrange the following bonds in order of DECREASING polarity.  Br—ClH--Cl  Cl—ClI--Cl  Cl--F

24. Partial Charges  Exist in polar covalent molecules  Demonstrates tendency of one end to be “slightly” negative or positive  NO charge on the whole molecule

25. Example 1: H 2 O

26. Example 2: PH 3

27. Homework  Chemical Bonding I Worksheet