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Covalent bonding

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Covalent bonding Covalent bond: A chemical bond formed when two atoms share electrons. Covalent bonding Covalent bond: A chemical bond formed when two atoms share ... – PowerPoint PPT presentation

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Title: 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

6
Electron dot diagram
  • C O H N F
  • Review What number of valence electrons do atoms
    want in order to be stable?

7
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
  • 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.

9
  • 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
10
Helium
Thus hydrogen only needs one more valence
electron to be stable. Helium is already stable.
11
Examples of covalent bonds/molecular compounds
  • F

12
Examples of covalent bonds/molecular compounds
  • F F

F2
13
Examples of covalent bonds/molecular compounds
  • F F O

F2
14
Examples of covalent bonds/molecular compounds
  • F F O H
  • H

F2
15
Examples of covalent bonds/molecular compounds
F F O H H
F2
Water molecule H20
16
Examples of covalent bonds/molecular compounds
O
17
Examples of covalent bonds/molecular compounds
O O
18
Examples of covalent bonds/molecular compounds
O O
Oxygen molecule O2 (double bond)
19
Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
H3N
20
Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
N
H3N
21
Examples of covalent bonds/molecular compounds
O O
Oxygen molecule H20 (double bond)
H
N
H
H3N
H
22
Examples of covalent bonds/molecular compounds
C02
23
Examples of covalent bonds/molecular compounds
C02
C
24
Examples of covalent bonds/molecular compounds
C02
O
C
25
Examples of covalent bonds/molecular compounds
C02
O
C
O
26
Examples of covalent bonds/molecular compounds
C02
O
C
O
double bond
27
Examples of covalent bonds/molecular compounds
N2
N
28
Examples of covalent bonds/molecular compounds
N2
N
29
Examples of covalent bonds/molecular compounds
N2
N
N
30
Examples of covalent bonds/molecular compounds
N2
N
N
triple bond (this is the maximum number of bonds
possible)
31
More aboutmolecular compounds
  • Atoms in molecular compounds do not have strong
    plus-minus charges.
  • Thus less heat is needed to melt or boil
    molecular solids.
  • Salt (an ionic compound) melts at 801 C. Sugar
    (a molecular compound) melts at 185 C.

32
  • Because electrons do not move between the atoms,
    molecular compounds do not conduct electricity
    well.

33
  • Because electrons do not move between the atoms,
    molecular compounds do not conduct electricity
    well.
  • This includes compounds such as rubber and
    water, which do not conduct electricity.

34
Polar molecular compounds
  • Some atoms pull more strongly on the shared
    electrons than other atoms do.

35
Polar molecular compounds
  • Some atoms pull more strongly on the shared
    electrons than other atoms do.
  • As a result, the valence electrons move closer
    to the stronger atoms.

36
Polar molecular compounds
  • Some atoms pull more strongly on the shared
    electrons than other atoms do.
  • As a result, the valence electrons move closer
    to the stronger atoms.
  • Since electrons have a negative charge, the
    strong atom will now have a slightly negative
    charge, and the weaker atom a slightly positive
    charge.

37
Nonpolar bond
  • F F

Equal pull
38
Polar bond
-
  • H F


Unequal pull
39
Water is a polar bond
  • Electrons are
  • pulled toward
  • the oxygen
  • atom.

40
Water is a polar bond
  • Electrons are
  • pulled toward
  • the oxygen
  • atom.
  • This causes cohesion The attraction that occurs
    between particles of the same substance.

41
Can you think of examples of waters cohesion
(holding together)?
42
Can you think of examples of waters cohesion
(holding together)?
Water droplets
43
Can you think of examples of waters cohesion
(holding together)?
Surface tension
44
Can you think of examples of waters cohesion
(holding together)?
Water transport in plants http//www.youtube.com/
watch?vCT4pURpXkbY
45
Why dont oil and water mix?
46
Why dont oil and water mix?
  • The polar water molecules are attracted more
    strongly to each other than they are to the
    nonpolar oil molecules.

47
Why dont oil and water mix?
  • The polar water molecules are attracted more
    strongly to each other than they are to the
    nonpolar oil molecules.
  • Soap molecules are polar on one end and nonpolar
    on the other.

48
Why dont oil and water mix?
  • The polar water molecules are attracted more
    strongly to each other than they are to the
    nonpolar oil molecules.
  • Soap molecules are polar on one end and nonpolar
    on the other.
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