Covalent bonding

1
Covalent bonding

• Covalent bond A chemical bond formed when two
  atoms share electrons.

2
Covalent bonding

• Covalent bond A chemical bond formed when two
  atoms share electrons.
• Co means together, joint, jointly.

3
Covalent bonding

• Covalent bond A chemical bond formed when two
  atoms share electrons.
• Co means together, joint, jointly.
• Double bond When two pairs of electrons are
  shared between atoms.

4
Covalent bonding

• Covalent bond A chemical bond formed when two
  atoms share electrons.
• Co means together, joint, jointly.
• Double bond When two pairs of electrons are
  shared between atoms.
• Molecular compounds Molecules formed through
  covalent bonding.

5
Electron dot diagram

• C O H N F

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Electron dot diagram

• C O H N F
• Review What number of valence electrons do atoms
  want in order to be stable?

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Electron dot diagram

• C O H N F
• Review What number of valence electrons do atoms
  want in order to be stable?
• Answer 0 or 8

8
Electron dot diagram

• C O H N F
• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?

9

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are . . .

10

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are INCORRECT.

11

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are INCORRECT.
• How many protons does helium have?

12

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are INCORRECT.
• How many protons does helium have? 2

13

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are INCORRECT.
• How many protons does helium have? 2
• How many electrons does it have?

14

• True confessions time. Mr. Spadoni lied to you in
  the last chapter.
• How many valence electrons does helium have?
• If you answered 8, because it is in family 18,
  you are INCORRECT.
• How many protons does helium have? 2
• How many electrons does it have? 2

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So how can it be stable if it doesnt have 8
valence electrons the way the rest of the noble
gases do?
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So how can it be stable if it doesnt have 8
valence electrons the way the rest of the noble
gases do?
Look at the electron configuration of
oxygen. Note that it has two electrons on the
inner shell, and then six on the outer shell. It
needs two more valence electrons to be
stable. The inner shell can only hold two. Helium
has only two total electrons, so its outer shell
is full. This makes it stable, like the other
noble gases that have full outer shells of eight.
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So how can it be stable if it doesnt have 8
valence electrons the way the rest of the noble
gases do?
Look at the electron configuration of
oxygen. Note that it has two electrons on the
inner shell, and then six on the outer shell. It
needs two more valence electrons to be
stable. The inner shell can only hold two. Helium
has only two total electrons, so its outer shell
is full. This makes it stable, like the other
noble gases that have full outer shells of eight.
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Electron dot diagram

• C O H N F
• Atoms want 0 or 8 valence electrons to be stable.
• However, there are two exceptions hydrogen and
  helium. They are stable when their inner shell of
  2 is filled.

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• Atoms want 0 or 8 valence electrons to be stable.
  However, there are two exceptions hydrogen and
  helium. They are stable when their inner shell of
  2 is filled.

Helium
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Helium
Thus hydrogen only needs one more valence
electron to be stable. Helium is already stable.
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Examples of covalent bonds/molecular compounds

• F

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Examples of covalent bonds/molecular compounds

• F F

F2
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Examples of covalent bonds/molecular compounds

• F F O

F2
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Examples of covalent bonds/molecular compounds

• F F O H
• H

F2
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Examples of covalent bonds/molecular compounds
F F O H H
F2
Water molecule H20
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Examples of covalent bonds/molecular compounds
O
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Examples of covalent bonds/molecular compounds
O O
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Examples of covalent bonds/molecular compounds
O O
Oxygen molecule O2 (double bond)
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Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
H3N
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Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
N
H3N
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Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
H
N
H
H3N
H
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Examples of covalent bonds/molecular compounds
C02
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Examples of covalent bonds/molecular compounds
C02
C
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Examples of covalent bonds/molecular compounds
C02
O
C
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Examples of covalent bonds/molecular compounds
C02
O
C
O
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Examples of covalent bonds/molecular compounds
C02
O
C
O
double bond
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Examples of covalent bonds/molecular compounds
N2
N
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Examples of covalent bonds/molecular compounds
N2
N
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Examples of covalent bonds/molecular compounds
N2
N
N
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Examples of covalent bonds/molecular compounds
N2
N
N
triple bond (this is the maximum number of bonds
possible)
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Now do this one on your own
CH4
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Now do this one on your own
CH4
C