Covalent Bonding

1
Covalent Bonding
2
Enter the world of Organic Chemistry
3
Review Ionic Bonding
Electron Transfer
4
Formation of a Simple Salt
Na
Cl

NaCl

-
Na
Cl
5
Formation of a more Complicated Salt
Mg
Cl

MgCl2
2
-
-
2
Cl
Cl
Mg
6
Formation of a very Complicated Salt
Al
O

Al2O3
2
3
2-
2-
2-
3
3
O
Al
O
O
Al
7
Is electron sharing possible?
All halogens are diatomic
F2 Cl2 Br2 I2
8
Covalent bonding

• a bond in which electrons are shared.

9
basics of covalent bonding
What is a covalent bond?
A bond based on sharing electrons
10
Ionic, covalent, or metallic?

• NaCl
• F2
• I2
• MgCl2
• CO2
• NaOH
• Fe

• Ionic
• Covalent
• Covalent
• Ionic
• Covalent
• Ionic
• metallic

Metal present ionic or metallic (metallic if
alone)
11
Write electron dot structures for H, O, N, and C
Cl

• Example Cl
• 7 valence electrons

O
N
C
H
12
HONC if you love chemistry
lone pairs

• H
• O
• N
• C

Unpaired electrons
Unpaired electrons bonds
How many bonds?
13
Write electron dot formulas for H, O, N, C
14
HONC if you love chemistry
O
N
C
H

• H
• O
• N
• C

15
Molecular Models A powerful tool
16
2. Make a molecule with a formula of C2H6O
1. Make a molecule with a formula of H2O
Hydrogen (white) Oxygen (blue) Carbon (black)
Dimethyl ether
ethanol
isomers
Same formula, different structure
17
Write down the structure of the model shown.
http//www.molecularmodels.ca/molecule/modelfiles/
2-3-ol.html
18
Multiple Covalent Bonds
Single bonds
19
Try some multiple covalent bonds
Draw
N2
CO2
O2
CH2O
20
HONC if you love chemistry

• H
• O
• N
• C

21
Draw all possible isomers of C4H8
22
HONC if you love chemistry

• H
• O
• N
• C

23
Do these look right?

• Na-Na
• H3O
• Cl2
• MgCl2
• CH3
• NH4

• No (unless metal lattice)
• H2O
• OK
• OK
• CH4
• NH3

24
Bonding All elements
3 bonds 1 lone pair
25
Bond Dissociation energies
26
Which has stronger bonds?

• CO2 or F2
• N2 or CH4

• CO2 (double bonds)
• N2 (triple bonds)

27
Naming Binary Covalent molecules

• H20
• NH3
• N2H4

• Dihydrogen monoxide
• (water)
• Nitrogen trihydride
• (ammonia)
• Dinitrogen tetrahydride
• (hydrazine)

28
Naming Binary Covalent molecules
29
Name Me

• Carbon tetrachloride
• Carbon monoxide
• Sulfur dioxide
• Boron trifluoride

• CCl4
• CO
• SO2
• BF3

30
Naming Covalent vs. Ionic

• NaCl
• CO
• AlCl3
• SO2
• FeO2
• SeO2

• sodium chloride
• Carbon monoxide
• Aluminum chloride
• Sulfur dioxide
• Iron(IV) oxide
• Selenium dioxide

• Keys
• Metals ionic no prefixes
• Transition metals ionic and charge must be
  specified.

31
Covalent BondingResonance Structures
andCharged covalent compounds
32
Atomic Charges on molecules
33
2 resonance structures of CO2
Zwitterion an internal salt
Wants 4 electrons Has 3 electrons Charge 1
Wants 6 electrons Has 6 electrons Charge 0
Wants 6 electrons Has 7 electrons Charge -1
Overall charge 0
34
You try it 2 resonance structures of formaldehyde
Wants 1 electron Has 1 electrons Charge 0
Wants 6 electron Has 7 electrons Charge 1
Wants 4 electron Has 3 electrons Charge 1
Overall charge 0
35
Show 3 resonance structures of the nitrate ion
36
What are molecules shaped like?
37
Now be careful!
38
Orbital hybridization
39
Polarity
40
Bonds and Polarity

• Paulings
• 0 nonpolar
• 0.1-1.7 polar covalent
• gt1.7 ionic

41
End Covalent Bonding