Chemical Bonding Covalent Bonding

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Chemical BondingCovalent Bonding

• Why and How Atoms Stick to each other

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Ionic Bonding

• Potential Energy Lowering
• Bond Formation Exothermic
• Types of Bonds
• Ionic
• Metal Nonmetal
• Transfer of e-(s) from Metal to Nonmetal

3
Ionic Bonding

• Potential Energy Lowering
• Bond Formation Exothermic
• Types of Bonds
• Ionic
• Large Difference between IE and eA of 2 elements
• Octet Rule - Atoms tend to have filled s p
  orbitals when bonding

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Periodic Table
Nonmetals much energy released with added e-

Metals little energy needed to remove e-
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Chemical Bonding

• Potential Energy Lowering
• Types of Bonds
• Covalent
• Nonmetal Nonmetal
• Octet Rule followed by Sharing e-(s)
• Small to zero difference between IE and eA of 2
  elements

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Chemical Bonding

• Potential Energy Lowering
• Types of Bonds
• Covalent
• Overlap of atomic orbitals allows sharing of
  e-(s)
• Overlapping atomic orbitals can be s - s, s-p,
  p-p, or other combinations of orbitals

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H to H Covalent Bonding
H 1s1
Potential Energy
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H to H Covalent Bonding
-435 kJ
H 1s1
Potential Energy
e- Shared by both H atoms
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H to H Covalent Bonding
HH Lewis Structure
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H to H Covalent Bonding
The overlap of the 2 half-filled orbitals
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H to H Covalent Bonding
The overlap of the 2 half-filled orbitals creates
a lower energy orbital containing both e-


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H to H Covalent Bonding
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H to H Covalent Bonding
Bond Length - Distance between two atoms where
the maximum amount of energy has been released
75 pm
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H to H Covalent Bonding
Bond Energy - Amount of energy release when bond
is formed
435 kJ/mol
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F to F Covalent Bonding
F He 2s2 2p5 One e- short of Octet
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F to F Covalent Bonding
Achieves Octet by Sharing a p e- from each F
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F to F Covalent Bonding
Producing a Sigma (?) Bond
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F to F Covalent Bonding
-158.3 kJ
F 2p5
F 2p5
Potential Energy
F2
e- Shared by both F atoms
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F to F Covalent Bonding


F F Lewis Structure



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H2 to F2 Bond Comparison
Compare Bond Energy and Length
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O to O Covalent Bonding
O He 2s2 2p4 Two p orbitals from each atom
need one e- each to have Octet
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O to O Covalent Bonding
Two p can overlap forming a Sigma Bond
O
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O to O Covalent Bonding
Two p can overlap forming a Sigma Bond
O
O
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O to O Covalent Bonding
A second pair of ps overlap forming a Pi Bond
O
O
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O to O Covalent Bonding
A second pair of ps overlap forming a Pi Bond
1 ? bond
O
O
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O to O Covalent Bonding
A ? plus a ? bond give O2 a double bond.
1 ? bond
O
O
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Multiple bonds

• Involve a Sigma plus one (for a double bond) or
  two (for a triple) Pi Bonds.
• Increased Number of Bonds release more energy
  when formed and require more energy to break

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Multiple Bonds

• The sideways overlap of P orbitals limits Pi
  bonds to small atoms (C, N, O, S, etc).
• Symbols use a Dash for a Bond
• e.g., H-H, F-F
• OO, H2CCH2
• N?N, C?N-

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Single, Double and Triple Bond
Compare Bond Length and Bond Strength