This document is part of a high school chemistry rapid learning series that provides a tutorial on chemical bonding. It begins by outlining the learning objectives of understanding the four main types of bonds - ionic, covalent, polar covalent and metallic - as well as bond polarity and valence bond theory. The tutorial then defines each type of bond and explains their characteristics. It also discusses bond polarity using electronegativity and introduces the valence bond theory of orbital overlapping. In concluding, it provides a summary of the key points learned.

1. High School Chemistry Rapid Learning Series - 15
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Chemical Bonding
HS Ch i t R id Learning Series
Chemistry Rapid L
i
S i
Wayne Huang, PhD
Kelly Deters, PhD
Russell Dahl, PhD
Elizabeth James, PhD
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2. High School Chemistry Rapid Learning Series - 15
Learning Objectives
By completing this tutorial you will learn…
4 types of bonds and the
properties associated with
those bond types.
Bond Polarity.
Valence Bond Theory.
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Concept Map
Previous content
Chemistry
New content
Ionic
Nonpolar
Covalent
C
l t
Polar
Covalent
Studies
Matter
4 types of bonding
One type is
Metallic
Compounds
Valance
Bond
Theory
Most simple bonding theory
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3. High School Chemistry Rapid Learning Series - 15
Types of
Chemical
Bonds
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Definition: Ionic Bond
Ionic Bond – Formed from the electrostatic
attraction between positive and negatively
charged ions due to transfer of electrons contains both metals and non-metals.
Na+
Cl-
A sodium atom loses an electron to form Na+ and a chlorine atom gains
that electron to form Cl-. An ionic bond is formed between them.
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4. High School Chemistry Rapid Learning Series - 15
Definition: Covalent Bond
Covalent Bond – Two nonmetals share electrons to
form a bond (e.g. CH4)
(e g
).
H
Sharing 4 pairs of electrons
between 4xH and 1xC atoms
H
C
H
H
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Definition: Polar Covalent Bond
Polar Covalent Bond –
Two non-metals share
electrons unevenly electrons are closer to
one atom than the
other.
H
C
N
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5. High School Chemistry Rapid Learning Series - 15
Definition: Metallic Bond
Metallic Bond – Metal
atoms join together and
j
g
pool their electrons in a
large network.
Cu
Cu
Cu
C
Cu
Cu
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Four Types of Bonds
The different bond types have different properties.
Happens
between
Electrons are
Characteristics
Metals & Nonmetals
Transferred from
one atom to
another to
create ions.
High melting points,
brittle, often dissolve in
water, conduct electricity
when aqueous.
Non-metals
Shared between
2 atoms.
Low melting points, do
not often dissolve in
water, do not conduct
electricity when aqueous.
Polar
Covalent
Non-Metals
Shared unevenly
between 2
atoms.
Medium melting points,
sometimes dissolve in
water, do not conduct
electricity when aqueous.
Metallic
Metals
Shared in a large
pool with all the
atoms.
Soft, conductors of heat
and electricity, do not
dissolve in water.
Ionic
Covalent
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6. High School Chemistry Rapid Learning Series - 15
Bond Polarity
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Definition: Polar Bond
Polar Bond – uneven sharing of
electrons due to differences in
electronegativity (i.e. CO2).
The “pull” an atom has for electrons
it’s sharing in a bond.
Oxygen is more electronegative than Carbon.
The Oxygen will pull on the electrons harder.
The electrons will move closer to the Oxygen
Oxygen.
δ+
δ-
O
C
δ-
O
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This will leave the Carbon
with a partial positive
charge and Oxygen with a
partial negative charge.
Note: Due to its symmetry,
CO2 molecule is nonpolar.
Its linear structure does
not have any overall
polarity because the two
polar bonds cancel each
other out.
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7. High School Chemistry Rapid Learning Series - 15
Electronegativity Trends
In general, electronegativity:
Increases
Decreases
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Common Element Electronegativities
Here are 8 common elements & their electronegativities.
Element
H
2.1
C
2.5
N
3.0
O
3.5
F
4.0
S
2.5
Cl
3.0
Br
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Electronegativity
2.8
Electronegativity Mnemonic: F > O > N > Cl > Br > S > C > H = FON
(fun) Clown Brings Such CHaos.
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8. High School Chemistry Rapid Learning Series - 15
Determining a Polar Bond
1
Look up the electronegativities for the two atoms.
2
Determine the (absolute value) difference in
electronegativity.
electronegativity
Differences of:
0
0.4 = Non-polar covalent bond
0.5
1.4 = polar covalent bond
> 1.4 = ionic bond
3
If there is a polar bond, indicate it with an arrow
being drawn toward the more electronegative
element with a cross on the tail.
Example:
C–H
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Determine if each is a polar bond.
C = 2.5
H = 2.1
Difference = 0.4
Non-polar
C–N
C = 2.5
N = 3.0
Difference = 0.5
Polar
Definition: Polar Molecules
Polar Molecule – Polar bonds do not cancel
out and the molecule overall has partially
positive and partially negative areas.
areas
δ-
O
C
O
O
H
H
δ+
Polar bonds, but non-polar molecule
Polar bonds, polar molecule
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9. High School Chemistry Rapid Learning Series - 15
Polar Molecules and Bond Geometry
The manner in which we draw a molecule could
affect our determination of polarity.
δ
δ-
O
H
O
H
H
H
δ+
Drawing water in this way makes
it appear to be a non-polar
molecule. Wrong!
However, water actually is shaped
like this, and it is a polar molecule.
It is important to know the actual 3D arrangement to determine polarity
of a molecule.
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Determining
Bond Types
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10. High School Chemistry Rapid Learning Series - 15
Bond Type Flow Chart
Compound
contains
Metal &
Non-metal
Ionic
Bonding
(MgCl2)
Non-metals
only
Electronegativity Electronegativity
difference
difference
0 - 0.4
0.5 – 1.4
Covalent
Bonding
(Cl2)
Metals
only
Metallic
Bonding
(Mg metal)
Polar
Covalent
Bonding
(HCl)
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Determining Bond Type Example
Example:
Determine the bond type of each:
K–O
Metal & non metal
non-metal
Ionic Bonding
C–O
Non-metals
C = 2.5
O = 3.5
Difference = 1.0
Polar Covalent
C–S
Non-metals
C = 2.5
S = 2.5
Difference = 0
Covalent
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11. High School Chemistry Rapid Learning Series - 15
Valence Bond
Theory
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Definition: Valence Bond Theory
Valence Bond Theory – Bonds are formed
by the orbitals of atoms overlapping
overlapping.
Valence Bond
H
H
H
H
s-orbital
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Valence Bond – A chemical bond formed by sharing valence electrons. A
valence electron, for a main group element, is in the outermost electron
shell. For a transition metal, it can also be in an inner shell.
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12. High School Chemistry Rapid Learning Series - 15
Sigma & Pi Bonds
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Definition: Sigma Bond - 1
Sigma Bond (σ bond) – A bond in which one
pair of electrons is shared. It is formed from
the overlap of 2 s-orbitals as below (head to
s orbitals
(head-tohead overlap).
H
H
s-orbital
2 hydrogen atoms - each has 1 electron in an
s-orbital.
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13. High School Chemistry Rapid Learning Series - 15
Definition: Sigma Bond - 2
Sigma Bond (σ bond) – A bond in which one
pair of electrons is shared. It is formed from
the overlap of 2 s orbitals as below (head to
s-orbitals
(head-tohead overlap).
sigma bond
H
H
H
H
2 hydrogen atoms - each have 1 electron in an s-orbital.
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As the atoms move together, their s-orbitals overlap
and form a sigma bond.
Definition: Pi Bond - 1
Pi Bond (π bond) – 2nd or 3rd bond between two
atoms. It is formed from parallel p-orbitals
(side-to-side overlap).
p-orbital
O
O
s-orbital
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Only the orbitals and
electrons involved in this
bond will be shown.
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14. High School Chemistry Rapid Learning Series - 15
Definition: Pi Bond - 2
Pi Bond (π bond) – 2nd or 3rd bond between
two atoms. Formed from parallel p-orbitals
(side-to-side overlap).
pi bond
O
O
O
O
sigma bond
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Counting Bonds
How many sigma and pi bonds are in a molecule?
σ
Each first bond between 2 atoms is a sigma bond.
π
All 2nd and 3rd bonds between 2 atoms are pi
bonds.
Example:
Count the sigma and pi bonds in the following molecule:
H H
H C C C N
σ
6
5
4
3
2
1
π
3
2
1
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15. High School Chemistry Rapid Learning Series - 15
Diatomic and Polyatomic Compounds
The Valence Bond Theory
works well for diatomic
compounds (H2, O2, etc.).
But what about polyatomic
compounds, such as CH4?
More complex theories, such as Hybridization
and Molecular Orbital Theory are introduced in
more advanced chemistry courses.
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Learning Summary
The type of bond can
be determined from the
atoms involved, and
each type has common
properties.
The Valence Bond
Theory uses the
overlap of atomic
orbitals for diatomic
compounds.
The first bond between
two atoms is a σ bond,
each addition bond is a
π bond.
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16. High School Chemistry Rapid Learning Series - 15
Congratulations
You have successfully completed
the tutorial
Chemical Bonding
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