1. Chemical Bonding
Chapter 6
Pages

2. The breaking of bonds and the forming of bonds occur during chemical reactions.

3. Aspirin What is the formula for a molecule of aspirin?
Is it an ionic or covalent (molecular) compound?
What do we call the things that hold a molecule of aspirin together?
C9H8O4
covalent compound (made of all nonmetals - no ions)

4. Aspirin
C9H8O4
covalent compound (made of all nonmetals - no ions)

5. Aspirin (Odyssey Program)
C9H8O4
covalent compound (made of all nonmetals - no ions)

6. The Attachment Between Atoms
atoms combine to form
ionic bonds covalent bonds
(M + NM) (NM + NM)
chemical bond – a mutual electrical attraction between the nuclei and valence electrons of two atoms that binds the atoms together

7. Ionic Bonding cation and anion
ionic bond – electrical attraction between cations and anions; when electrons are taken by one atom from another atom
metal and a nonmetal
NaCl
cation and anion
(The charges are “hidden” to make a neutral compound.)

8. Ionic Bonding: taking of electrons
Na 11e-
F 9e-
Na+ 10e- STABLE!!!
F- 10e- STABLE!!! 3s 3s 2p 2p 2s 2s 1s 1s

9. + - I’m Positive! I’m Negative A metal atom A metal ion A nonmetal ion
A nonmetal atom
I’m Positive!
I’m Negative + -

10. Ionic bonding!!! I’m Positive! I’m Negative
A metal ion
A nonmetal ion
I’m Positive!
I’m Negative
When a metal and a nonmetal atom are around each other there is the opportunity for….
…the transfer of electrons producing ions that would like to cling to each other.
Ionic bonding!!!

11. The simplest ratio of the packed ions is called:
“cubic”
shape
The Formula Unit Ex: NaCl

12. Metals form cations. (metals lose e-) Nonmetals form anions.
(nonmetals gain e-)

13. Ions cations (+) anions (-) monatomic ions – ions
formed from one atom Examples: Na+ or O-2
polyatomic ions - ions formed from two or more atoms bonded together
Examples: NH4+ or SO4-2

14. Naming Ions monatomic ions polyatomic ions
cations – named like the atom, only add ion to it
Example: Na+
is the sodium ion
anions – remove the ending to the atom name and add –ide and ion to it
Example: Cl-
is the chlorine
+ide ion
or the chloride ion
polyatomic ions
You do not determine their names, you memorize them

15. Ionic Compounds solid at room temperature (forming crystals)
high melting points (thus are usually solid at RT)
formula unit represents the lowest ratio of ions that combine to form a neutral compound
when dissolved in water, the ionic compounds will break up into ions (dissociate)
the solutions of ionic compounds will conduct electricity (electrolytes)

16. Dissociation solid placed in water hydrated ions (surrounded by water)
dissociation – when an ionic compound dissolves to break apart into hydrated ions

17. Dissociation

18. Electrolytes and Nonelectrolytes
When an ionic compound dissolves to produce ions, it is called an electrolyte because it conducts electricity in water.
When an compound does not dissolve to produce ions, it is called a nonelectrolyte because it does not conduct electricity in water.

19. Electrolytes or salt?

20. Check for Understanding
What kinds of atoms form ionic bonds?
What is a polyatomic ion?
Name 5 things you learned about ionic compounds.

21. You Try It.
Do the Dissociation Equations worksheet.

22. Covalent Bonding
covalent bond – when electrons are shared between two atoms
the electronegativity difference between the two atoms is less than 1.7
usually two nonmetals
NO ions formed! (no electrons are taken…just shared)

23. When a nonmetal and another nonmetal atom are around each other there is the opportunity for….
…the sharing of electrons producing molecules in which the atoms like to cling to each other.
Covalent bonding!!!

24. The formation of a bond between two nonmetal atoms.
Atoms sufficiently far apart to have no interaction

25. Figure 5 Page 179

26. Covalent Compounds Also called molecular compounds
solid, liquid, or gas at room temperature
low melting points
molecular formula represents the actual ratio of atoms that combine to form a neutral compound
when dissolved in water, the molecular compounds DO NOT break up into ions
(NO dissociation)
the solutions of molecular compounds DO NOT conduct electricity (nonelectrolytes)

27. The two fundamental types of bonds.
Pure Covalent
The two fundamental types of bonds.
Ionic

28. There is another type of bond, not purely covalent and not purely ionic.
Nonpolar Covalent
Pure Covalent
Polar Covalent
Ionic

29. Sharing of Electrons
How would you know if an electron is going to be taken by one atom from another?
Is there ever a time in which the electron is not taken but shared?
Is the electron always shared equally?

30. Electronegativity
electronegativity – a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound
The difference in electronegativity values for two atoms will indicate whether the two atoms form an ionic bond (e- taken) or a polar or nonpolar covalent bond (e- shared).

31. Electronegativity Differences
0.0 to 0.49 nonpolar covalent
0.5 to 1.69 polar covalent
1.7 and up ionic
These ranges are flexible, although the general rule is a metal and nonmetal will form an ionic bond and two nonmetals will form a covalent bond.
(Learn these values!)
PS: They are different than your book!

32. Ionic, Polar Covalent, or Nonpolar Covalent?
What kind of bond would each pair form?
N and S
S and C
Mg and Cl
C and F
Ba and O
Which one of these bonds has the least ionic character?

33. Valence Electrons
valence electrons – the electrons in the highest energy level
Na: 1s22s22p63s valence e-
O: ? Ne: ? Al: ? He: ?

34. Octet Rule
octet rule – most atoms will gain or lose electrons to have 8 valence electrons (e- in the highest energy level)
Exceptions: H, He, Li, Be, B, and some atoms P and higher on the periodic table
Why is an atom like Ca more stable once it becomes an ion?
How many valence electrons would calcium have to lose to have 8?

35. Valence Shell Electron Pair Repulsion Theory VSEPR Theory
Repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far apart as possible.

36. Regions of Electron Density
What is a Region of electron density?
Single bond (2e- connecting 2 atoms)
Double bond (4e- connecting 2 atoms)
Triple bond (6e- connecting 2 atoms)
Lone pair (unbonded pair) (2e- alone on an atom)

37. LINEAR 180o 2 Regions of Electron Density 2 Bonds
bonded pair of electrons
bonded pair of electrons

38. TRIGONAL PLANAR 120o 3 Regions of Electron Density 3 Bonds
3 bonded pairs of electrons

39. BENT 119o 3 Regions of Electron Density 2 Bonds & 1 Lone Pair
You don’t have to know this!
BENT 119o 3 Regions of Electron Density 2 Bonds & 1 Lone Pair
2 bonded pairs of electrons
1 lone pair of electrons

40. TETRAHEDRAL 109.5o 4 Regions of Electron Density 4 Bonds
4 bonded pairs of electrons

41. TRIGONAL PYRAMIDAL 107o 4 Regions of Electron Density 3 Bonds & 1 Lone Pair
1 lone pair of electrons
3 bonded pairs of electrons

42. BENT 105o 4 Regions of Electron Density 2 Bonds & 2 Lone Pairs

43. All of these have 4 regions of electron density
(although the number of bonded pairs is different)

44. TRIGONAL BIPYRAMIDAL 120o & 90o 5 Regions of Electron Density 5 Bonds

45. You don’t have to know this!
SEE-SAW 120o & 90o 5 Regions of Electron Density 4 Bonds & 1 Lone Pair
You don’t have to know this!

46. You don’t have to know this!
T-SHAPED 120o & 90o 5 Regions of Electron Density 3 Bonds & 2 Lone Pairs
You don’t have to know this!

47. You don’t have to know this!
LINEAR 180o 5 Regions of Electron Density 2 Bonds & 3 Lone Pairs
You don’t have to know this!

48. OCTAHEDRAL 90o 6 Regions of Electron Density 6 Bonds
SF6

49. You don’t have to know this!
SQUARE PYRAMIDAL approximately 90o 6 Regions of Electron Density 5 Bonds & 1 Lone Pair
BrF5
You don’t have to know this!

50. SQUARE PLANAR 90o 6 Regions of Electron Density 4 Bonds & 2 Lone Pairs
ICl4-