1. Section 1A

2. Bonding II: Types of substances
1) Ionic compounds = continuous Ionic bonding
between weak loser metal and strong gainer nonmetal
ex: NaCl Sodium Chloride

3. Honors: Traditional system for Ionic
Latin suffix with endings
-ic (higher charge)
or –ous (lower Charge)
Ex: copper +1 OR +2 oxidation states
Copper (I) oxide Copper (II) oxide
Cu2O CuO
Cuprous oxide cupric oxide
Others: Ferrous / Ferric Fe = iron
Stannous / Stannic Sn = tin
plumbous / plumbic Pb = lead
What is the formula for ferrous chloride?
FeCl2

4. Bonding II: Types of substances
1) Ionic compounds = continuous Ionic bonding
between weak (loser) metal and strong (gainer) nonmetal
2) molecular compounds = covalent bonding inside molecules
= IM forces between molecules
between strong nonmetals
ex: SO2 Sulfur (IV) oxide
Organics – with Carbon
ex: CH4 methane
Acids – with H as the loser
ex: HCl hydrogen chloride

5. Organic molecular compounds (vs. inorganic)
- Based on chain of carbon with H and other nonmetals attached.
Many molecular formulas can be reduced (simplified) to empirical (ratio) formulas
Ex: glucose
molecular formula: C6H12O6
empirical formula:
CH2O
6:12:6 = 1:2:1 ratio 6

6. Problem: What is the empirical formula for the molecular formula C6H8?
6:8 = 3:4 ratio 2
C3H4

7. Hydrogen compounds Hydrogen sulfide Hydrogen sulfate Water
H+ forms molecular (covalent) compounds with other nonmetals.
named like ionic compounds when in their pure state
ex: HCl hydrogen chloride
others: 1. H2S
2. H2SO4
3. H2O
4. H2O2
Hydrogen sulfide
Hydrogen sulfate
Water
Hydrogen Peroxide
H- in back are hydrides
Ex: Metal hydrides
KH potassium hydride
[O2]2- polyatomic ion
(Sodium peroxide = Na2O2)

8. Acids: H+ compounds (aq) in water
Has properties of both ionic and molecular
Made of molecules, but can break into ions in water
Ex: HCl (g) → HCl (aq) = ( Separate H+ & Cl- ions )
H2O
Hydrogen
chloride
Hydrochloric
acid
Unlike typical molecular compounds:
acids are Gases and liquids that are soluble in water
Solutions conduct electricity like ionic

9. NaCl (aq) C6H12O6 (aq)
HCl (aq) ?

10. Acids w/
H in front Or
COOH at end

11. Bonding II: Types of substances
1) Ionic compounds = continuous Ionic bonding
2) molecular compounds = covalent bonding inside molecules
Organic – with Carbon
Acids – turn ionic in water
3) Network substances = continuous covalent bonding
- C and Si Crystals
- Elements that form 4 bonds (bonds in all directions)

12. Network Solids: Molecular: Discrete Particles Ex: H2O | | |
Continuous covalent bonds
Hard, very high melting points
Elements which form 4 bonds
Ex: diamond (C), Sand (SiO2)
| | |
--- C --- C --- C ---
| | |
| | |
Weak forces
Between molecules =
Low MP

14. Bonding II: Types of substances
1) Ionic compounds = continuous Ionic bonding
2) molecular compounds = covalent bonding inside molecules
3) Network substances = continuous covalent bonding
4) Metallic (pure and mixtures – alloys)
continuous metallic bonds

15. Learning Check: What are the four types of pure “substances”
How can bonding type be surmised from the chemical formula of a substance?
What identifies a compound as organic?
Is the formula H2O an empirical or molecular formula?
What identifies a substance as an acid? How is it different from other molecular substances?
What kind of bonding is in a network structure? How is it different from molecular structures?

16. Section 1B

17. Polarity in covalent (sharing) bonds
Bond Polarity: Balance of charge in bonding is due to the difference in pull on electrons (atoms don’t share equally)
No polarity
Polar bond
Atoms of same element
BrINClHOF’s
Bond is nonpolar
Atoms of different elements
Electrons pulled toward
stronger atom. Bond is “polar”

18. Problems Same = nonpolar Different nonmetals Ionic, not covalent
Which contain molecules with polar covalent bonds?
H2(g)
HCl (g)
CCl4(l)
NaCl (s)
Fe (s)
Same = nonpolar
Different nonmetals
Ionic, not covalent
Metallic bonds

19. Electronegativity (pulling strength)
Ability of an atom to attract a pair of bonding electrons to itself
Metals
Weak
Fr is
Least
Electro-
Negative
(“electro-positive”)
Nonmetals
Strong
F is
Most
Electro-
negative
increasing
decreasing

20. some polarity in the bond Highest polarity is ionic bond
Bond “Character”
Depends on difference in electronegativity between bonded atoms
NaF HF OF F-F
= 0
No polarity in the bond
4.0 – 2.1 = 1.9
high polarity in bond
4.0 – 3.5 = 0.5
some polarity in the bond
4.0 – 0.9 = 3.1
Highest polarity is ionic bond
100% covalent character
Most ionic character
Further apart = more polarity = more ionic character

21. Bond “Character” NaF HF OF2 F-F 3.1 1.9 0.5 0.0
Difference in electronegativity between bonded atoms
NaF HF OF F-F
 
most polar fairly polar less polar no polarity
Ionic character covalent character
 
Ionic polar covalent nonpolar covalent

22. Practice problems 2.1- 2.1 = 0.0 Strongest gainer With H 4.0- 2.1 =
1. Which bond is most polar?
a. H-H
b. H-F
c. H-O
d. H-I
2. Which substance has the greatest ionic character?
a. C-Cl
b. H-Cl
c. Cl-Cl
d. Na-Cl =
0.0
Strongest gainer
With H =
1.9
1.4
0.6
(Greatest polarity)
= 0.6
1.1
0.0
2.3
Only ionic compound!

24. Section 1C

25. Molecule Polarity Negative Positive Pole Pole Ex: H --- Cl
Due to symmetry of bonds, molecules can be polar or nonpolar
A Polar molecule:
Is called a Dipole”  it has negative and positive poles (ends)
Is Asymmetrical (not symmetrical) in molecule shape
and not symmetrical in electron arrangement
Electrons pulled toward stronger Cl end of molecule
Dipoles
are
“sticky”
Positive
Pole
Negative
Pole
Ex: H --- Cl
molecules with different ends are Polar or “dipoles”

26. Nonpolar Nonpolar Nonpolar Nonpolar = symmetrical, “balanced”
Polar = asymmetrical, “unbalanced”
If it has a front, back, top or bottom its polar.
If its symmetrical its Nonpolar
Polar or nonpolar?
Nonpolar
Nonpolar
Nonpolar

27. Predicting Polarity (predicting shape)Ne
VSEPR Theory - used to predict the
shape and polarity of molecules
from Lewis electron dot structure
(Valence Shell Electron Pair Repulsion)
Four Electron pairs repel each other to the 4 corners of a tetrahedron arrangement
Bonded atoms get arranged
into different shapes
Ex: H2O angular
Tetrahedron
Vesper
Electron
Pairs
Act as
Bonded
atoms

28. Polar shapes: asymmetrical charge shape and charge distribution
Linear Polar
Ex: HF, HI, etc.
Two different elements
Angular (bent) polar
Ex: H2O, OF2 x H x O F O F x I H x
Angular Or straight? Why?
(+) H --- I (--)
(+) H --- O (--) | H
(+)

29. N H X H x Pyramid (Trigonal) Ex: NH3 Vesper electron pair
pushes other Atoms
into a pyramid Shape!

30. Nonpolar molecule shapes
Symmetrical shape and distribution of electron charge
Look for C or Si in compounds
Linear nonpolar
Ex: BrINClHOF’s CO2, CS2
O=C=O
All C’s electrons are in the bond
No Vesper electron pair to push O x C
Notice: nonpolar compounds
usually contain C

31. Tetrahedral molecules CH4 or CCl4
Structural formula
Structural formula: each line = 2 electrons
Notice: CX4

32. Less common shapes: Trigonal Planer
Nonpolar
BF3
Polar
CH2O

33. Learning check: Predict the shape of each molecule
and if it is Polar or Nonpolar:
1. O He
2. CCl N2
3. HCl OF2
4. H2O CH2F2
5. NF PCl3
6. CS NH4+

35. Section 2A

36. Intermolecular (“sticky”) forces
Called Vanderwaal’s forces (“IM” forces)
Weak Physical force between adjacent molecules
(ex: determines how high melting points will be)
Affected by polarity (shape) of molecules
(Negative pole attracted to positive pole)
Allows molecular substances to exist as liquids and low melting point solids (instead of gases)
Two types: dipole attractions and dispersion forces

37. HF is more polar = stickier
Polar molecules (dipoles) are attracted to each other.
Depends on extent of molecules polarity
(ex: HCl vs. HF)
Hydrogen bonds
special type
H bonded to small,
strong atom: F, O, or N
Found between molecules in HF, H2O, NH3
Accounts for higher than expected MP and BP
“Dipole Attractions”
HF is more polar
= stickier
H is a
naked
proton

38. What kind of question is this:
Notice all have H bonded to another nonmetal
Hydrogen bonding!

39. Dispersion forces “Big and sticky force”
In large and Nonpolar molecules
Random Dispersion of electrons creates temporary (+) and (-) poles
Stronger in molecules with more electrons (larger) and as molecules get closer
Ex: liquefaction of gases only at high pressure (molecules forced together)
Ex: wax, dry ice (CO2(s))
“Big and sticky force”
What explains the pattern of phases in group 17?

40. Phase change / boiling point questions:
Usually relate to IM (sticky) forces
Low temp = weak IM forces

41. At STP, both at same temperature
46 At STP, fluorine is a gas and iodine is a solid.
This observation can be explained by the fact
that fluorine has
(1) weaker intermolecular forces of attraction than iodine
(2) stronger intermolecular forces of attraction than iodine
(3) lower average kinetic energy than iodine
(4) higher average kinetic energy than iodine
gas = weaker IM forces
F2 smaller than I2
Average Kinetic energy  Ie. How fast molecules are moving = Temperature
At STP, both at same temperature

43. What IM forces are responsible?
Recall:
Organics
are
mostly
Nonpolar
Acetone
C3H6O
Propane
C3H8
Octane
C8H18
Glycerol
C3H4(OH)3

44. IM force?
Mostly dispersion forces
Acetone
C3H6O
Acetone is the liquid in fingernail
Polish remover that makes it dry quickly

45. IM force?
Mostly dispersion forces
Propane
C3H8
Propane is the gas used for heating many homes

46. Glycerol is a viscous liquid used to make cake frosting creamy
IM force?
some dispersion forces
Notice the OH group?
Hydrogen bonding!
Glycerol
C3H4(OH)3

47. Octane is one of the liquids in gasoline
IM force?
dispersion forces
Octane
C8H18

48. Can you explain the trends?

49. Practice problems:
Which liquid contains the strongest intermolecular forces: He(l), Ne(l), Ar(l), Or Kr(l)? Why?
2. Which has the strongest Hydrogen bonds? H2, HF, HCl, or HBr?
3. Which is expected to have the lowest Boiling point? F2, Cl2, Br2, or I2?
What two kind of bonds are found in a sample of H2O(l)?

51. Boiling point questions: Usually relate to IM (sticky) forces
41 Based on intermolecular forces, which of these
substances would have the highest boiling point?
(1) He (3) CH4
(2) O2 (4) NH3
Polar / H-bonds = strongest IM forces, highest BP
23 Hydrogen bonding is a type of
(1) strong covalent bond
(2) weak ionic bond
(3) strong intermolecular force
(4) weak intermolecular force
Oxymoron: Strongest of the weak forces!

52. Each molecule listed below is formed by sharing electrons between atoms when the atoms within the molecule are bonded together.
Molecule A: Cl2
Molecule B: CCl4
Molecule C: NH3
59 Explain why NH3 has stronger intermolecular forces of attraction than Cl2. [1]
60 Explain why CCl4 is classified as a nonpolar molecule [1]
61 Explain how the bonding in KCl is different from the bonding in A, B, and C [1]

53. Section 2B

54. Distinguishing between substances: Ionic compounds = Ionic bonding
molecular compounds = covalent bonding
metallic – pure or alloys = metallic bonds
Network substances = covalent bonding
Based on properties: Melting or boiling point / phase
Solubility in water
Electrical conductivity

55. Electrical conductivity
What is required to conduct electricity?
Metals: yes as solid or liquid
Ionic salts:
no when solid, yes when (aq) in H2O
or when fused (melted) into liquid
Molecular – no, except acids when (aq) in water
Requires particles which are:
(1) charged AND (2) mobile
Mobile electrons
Mobile ions
Mobile ions
Electrolyte: substance that conducts electricity when dissolved in water
Includes ionic salts and acids
Ex: NaCl, HCl

56. Metals w/ mobile
electrons
Molecular have
Neutral molecules
Ionic
w/ mobile
Ions when
dissolved

57. Ions in water Allow acids to Conduct electricity
Strong acids = lots of ions formed
Weak acids = few ions formed

58. Properties of solids Ionic molecular metallic network
Strong Weak Continuous strong
Continuous intermolecular flexible continuous
Ionic bonds forces metallic bonds covalent bonds
Brittle solids soft solids malleable very hard
High MP low MP MP varies extremely high MP
Usually soluble not usually soluble NO NO
In water in water solubility solubility
Conductors:
as (l) or (aq) Poor conductor good conductor poor conductor
(mobile ions) (neutral particles) (mobile electrons) (nothing is mobile)

59. Review problems What kind of Substance?
A white crystalline substance, conducts when dissolved in aqueous solution.
A soft solid, melts at 75 0C. Nonconductor
Silvery grey solid. Good electrical conductor
Crystalline solid. Melts at 10000C. Nonconductor.
White crystalline solid. Dissolves easily, but aqueous solution doesn’t conduct electricity

60. Review problems:
What kind of bond accounts for these properties? (Describe)
White crystalline solid, melts at 7000C. Conducts electricity as a when fused (melted).
A liquid, evaporates readily.
A malleable solid.
A sticky viscous liquid.
Water’s high surface tension.

61. Sample questions H with small e- gainer
High melting point = strong forces:

62. Salts are soluble: ionic
Conducts e- when dissolved: ionic
Strong bonds:

63. Methane is CH4