Chemical Bonding - Georgia Institute of...
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1 Week 6 CHEM 1310 - Sections L and M 1 Chemical Bonding Types of Chemical Bonds – Ionic bonds – Coulomb’s Law – Covalent bonds Electronegativity Bond Polarity and Dipole Moments Week 6 CHEM 1310 - Sections L and M 2 PRS Question How many valence electrons does Ar have? 1. None 2. 1 3. 6 4. 8 5. 18 See Elmo screen for results… Week 6 CHEM 1310 - Sections L and M 3 Bonding and Electrons Types of electrons – Core electrons are found in filled shells – Valence electrons are found in the outermost shell Valence electrons participate in bonding through 2 ways: – Transferring electrons from one atom to another: ionic bonding – Sharing electrons between 2 atoms: covalent bonding
Transcript of Chemical Bonding - Georgia Institute of...
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Week 6 CHEM 1310 - Sections L and M 1
Chemical Bonding
Types of Chemical Bonds– Ionic bonds– Coulomb’s Law– Covalent bonds
Electronegativity
Bond Polarity and Dipole Moments
Week 6 CHEM 1310 - Sections L and M 2
PRS Question
How many valence electrons does Ar have?
1. None
2. 1
3. 6
4. 8
5. 18
See Elmo screenfor results…
Week 6 CHEM 1310 - Sections L and M 3
Bonding and Electrons
Types of electrons– Core electrons are found in filled shells– Valence electrons are found in the outermost shell
Valence electrons participate in bondingthrough 2 ways:– Transferring electrons from one atom to another: ionic
bonding
– Sharing electrons between 2 atoms: covalent bonding
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Week 6 CHEM 1310 - Sections L and M 4
Types of Bonds - Overview
Covalent
e.g., H2, Cl2 N2
Polar Covalent
e.g., HF, H2O
Ionic Bond
e.g., LiF, NaCl
Week 6 CHEM 1310 - Sections L and M 5
Ionic BondingWhen are ionic substances formed?
When an atom that loses e- easily reacts with an atom thatgains e- easily!
3p
3s
2p
2s
1s
Na has one unpaired valence electron that itcan easily lose.
Week 6 CHEM 1310 - Sections L and M 6
Ionic Bonding
3p
3s
2p
2s
1s
Cl is missing one e- that it can easily gain to make afilled shell.
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Week 6 CHEM 1310 - Sections L and M 7
Ionic Bonding
When are ionic substances formed?
Na · → Na+ + e-
e- + Cl → Gain of a valence electron: Cl :. .
. .-
: Cl :. .
. .-+Na+ → NaCl Combination forms the
compound NaCl
Loss of a valence electron
Week 6 CHEM 1310 - Sections L and M 8
Coulomb’s Law
The energy of interaction between a pair of ions canbe calculated by using Coulomb's law
F = force on each charge
k = electrostatic constant
r = separation distance
q1, q2 = charges
Week 6 CHEM 1310 - Sections L and M 9
Alternate Version of Coulomb’s Law
1 2
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QQV
rpe=
o
V = PotentialEnergy
ε0 = permittivity
Look thisup…
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Week 6 CHEM 1310 - Sections L and M 10
Potential Energy
Pote
ntia
l Ene
rgy,
kJ/
mol
Distance, nm
Negative PE values areattractive!
Positive PE values arerepulsive!
Week 6 CHEM 1310 - Sections L and M 11
Electrons are shared by the nuclei
Whenever possible, the valence electrons in acompound are distributed in such a way that each
main-group element in a molecule (except hydrogen) issurrounded by 8 electrons (an octet of electrons).
Hydrogen should have 2 electrons in such a structure.
H:Cl:··
··H· ·Cl:
··
··→ or H―Cl:
··
··
Covalent Bonding
