1. Chapter 6: Chemical Bonding Covalent Focus
6.1 Intro to Bonding
6.2 Lewis Structures
6.3 Covalent Formulas

2. 6.1 Intro to Bonding Learning Targets
Describe and explain chemical bonding.
Describe ionic and covalent bonding.

3. 6.1 Intro to Bonding Chemical Bond:
Force of attraction between two atoms
Due to mutual attraction of nuclei for electrons

4. 6.1 Intro to Bonding Why do atoms form bonds?
Bonds allow atoms to become more stable by achieving lower energy
Forming a bond releases energy
Breaking a bond absorbs energy
Atoms gain or lose electrons to achieve noble gas configuration (full shell)

5. 6.1 Intro to Bonding Octet Rule:
Atoms tend to gain, lose, or share electrons to get 8 valence electrons in order to achieve a noble gas configuration Li O Ne C

6. 6.1 Intro to Bonding Electronegativity
Measures how strongly an atom pulls electrons towards it

7. 6.1 Intro to Bonding What type of bond? Metals-metals: Metallic
Metal-nonmetal: Ionic
Nonmetal-nonmetal: Covalent
Polar if atoms are different from each other

8. 6.1 Intro to Bonding 1. H –C 2. N—N 3. Cu—Zn 4. Cs—F 5. C—F
Classify each of the following bonds:
1. H –C
2. N—N
3. Cu—Zn
4. Cs—F
5. C—F

9. 6.1 Intro to Bonding Ionic Bond
Bond formed by attraction between cation and anion
One atom loses e-, one gains e-

10. 6.1 Intro to Bonding Properties of Ionic Compounds 1. Crystalline
Orderly arranged pattern of cations and anions
2. Solid
3. High Melting/Boiling Points

11. 6.1 Intro to Bonding 4. Hard and Brittle 5. White or Bright colors
6. Dissolve in Water
7. Conduct electricity
Break apart into ions in water

12. 6.1 Intro to Bonding Covalent bond: Polar covalent:
Two atoms share electrons to gain an octet
Polar covalent:
Bond formed by two elements that have different electronegativity
Electrons spend more time with one atom
Slight charges on atoms
Dissolve in polar solvents (water, ethanol)

13. 6.1 Intro to Bonding Nonpolar covalent:
Bond formed by two elements that have the same or similar electronegativity
Electrons spend equal time with each atom
No charge on atoms
Dissolve in nonpolar solvents (hexane)

14. 6.1 Intro to Bonding Properties of Covalent Compounds
1. Crystalline or Amorphous
2. All phases
3. Soft
4. Low melting/boiling point

15. 6.1 Intro to Bonding 5. Dull Colors 6. Soluble based on polarity
Polar dissolve; Nonpolar do not
7. Nonconductors

16. 6.1 Intro to Bonding Metallic Bond
Positive nuclei (cations) exist separately in a sea of electrons

17. 6.1 Intro to Bonding Properties of Metals
1. Conduct heat and electricity
2. Malleable
3. Ductility
4. Lustrous

19. 6.2 Lewis Structures Learning Targets:
Draw Lewis dot structures for covalent molecules.
Determine the polarity of a molecule.
Use VSEPR to determine shapes of molecules.

20. 6.2 Lewis Structures Lewis Dot Structures Bonding Pair Lone Pair
Representation of molecules using nonbonding e-, bonding e-, and atoms
Bonding Pair
2 shared electrons
Lone Pair
2 electrons not in a bond

21. 6.2 Lewis Structures
1. Br2
2. N2
3. H2O
4. CH3I

22. 6.2 Lewis Structures
5. HNO
6. C2H6
7. C2H4

23. 6.2 Lewis Structures Polarity
Measure of uneven distribution of electrons throughout a molecule
2 things to look for
Asymmetry around central atom
Different elements
Lone pairs

24. 6.2 Lewis Structures Determine if polar or nonpolar 1. Br2 2. NH3
3. C2H6
4. CH3Cl
5. C2H4
6. H2O

25. 6.2 Lewis Structures
Octet Exceptions
B: BH3
I: IF3
Xe: XeF4

26. 6.2 Lewis Structures
Valence Shell Electron Pair Repulsion (VSEPR) theory:
Predicts shapes of covalent molecules using valence electrons and bonds
Electron pairs repel each other
Look at central atom (with most atoms attached)
Count atoms attached and lone pairs (only on central atom)

28. 6.3 Covalent Formulas Learning Targets:
Write names and formulas of covalent compounds.

29. 6.3 Covalent Formulas Monoatomic Diatomic Made of individual atoms
Made of 2 atoms covalently bonded
7 elements always found in pairs when pure element
Diatomic 7:
H2 , N2 , O2 , F2 , Cl2 , Br2 , I2

30. 6.3 Covalent Formulas Prefixes Prefix Number Mono- 1 Di- 2 Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10

31. 6.3 Covalent Formulas Writing a formula from a name: Only nonmetals
1. In order of name, write symbols
2. Prefixes determine subscript (# of atoms)
No prefix on 1st element  1 atom

32. 6.3 Covalent Formulas You try! 1. Dihydrogen monosulfide
2. Carbon tetrahydride
3. Iodine pentafluoride
4. Hydrogen monochloride
5. Triphosphorous pentoxide

33. 6.3 Covalent Formulas Naming a covalent compound Only nonmetals
1. In order of formula, write name of each element.
2. Add prefixes in front to show amount
If only 1 of first element, ignore “mono”
3. Change endings (all but first) to –”ide”

34. 6.3 Covalent Formulas
You try!
1. CO2
2. SeO
3. IF7
4. PH3
5. N2O5