COVALENT BONDS

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COVALENT BONDS
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Ionic Bond Review
Draw the electron diagram for sodium Draw the
electron diagram for chlorine (include protons,
neutrons, and electrons)
17
Chlorine
11
Sodium
11 11 -
17 17 -
11 10 -
17 18 -
17 19N
11 12N
0 (neutral)
0 (neutral)
1 (positive)
1- (negative)
7 Valence Electron
8 Valence Electron
1 Valence Electron
8 Valence Electron
1
-1
Na1 Cl-1 NaCl
3
-One way elements can bond together to form a
chemical bond is by forming ions and an ionic
bond. -The ionic bond forms because the
oppositely charged ions are _______________ to
each other . -Ions are formed when an atom or
group of atoms __________ or __________ valence
electrons to achieve the perfect ________.
attracted
gives
takes
8
Na
Cl
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COVALENT BONDS
Fluorine
9
Fluorine
9
9 10N
9 10N
7 Valence Electron
8 Valence Electron
7 Valence Electron
6 Valence Electron
5
COVALENT BONDS
Fluorine
9
Fluorine
9
9 10N
9 10N
7 Valence Electron
7 Valence Electron
Access to 8 Valence Electron
Access to 8 Valence Electron
Sharing Pool
-Bonds can be formed not only by taking or giving
electrons, but also by _________________
electrons. -A chemical bond formed when two atoms
share electrons is called a ____________________
bond.
sharing
covalent
together
valence
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For example -The Fluorine atoms could not
give or take electrons and still have both
atoms achieve the perfect _____. Instead they
shared.
F
F
8
7
Draw electron dot diagrams for H20
(water) NH3 (ammonia) Element Element diagra
ms diagrams Compound Compound diagram
diagram Hint Hydrogen can have no more
than two electrons and two electrons feels like
the perfect 8 to it.
H
O
H
N
H
H
H
H
O
H
N
H
H
H
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SPECIAL COVALENT BONDS Now try and draw the
electron dot diagrams for these molecules CO2
(carbon dioxide) N2 (nitrogen
molecule) Element Element diagrams diag
rams Compound Compound diagram diag
ram This type of bond is called This type
of bond is called a __________ covalent bond.
a ___________ covalent bond.
C
O
O
N
N
C
N
N
O
O
double
triple
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POLAR AND NONPOLAR MOLECULES FORMED FROM
COVALENT BONDS
Nonpolar molecules F2 (fluorine molecule) N2
(nitrogen) CO2 (carbon dioxide) -Elect
rons are shared equally, pulled equally, and
aligned linearly. Polar molecules HF (hydrogen
fluoride) H2O (water)
C
F
F
N
N
O
O
(equal pulling)
(equal pulling)
(equal pulling)
H
F
O
H
H
(unequal pulling)
(unequal pulling)
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Polar molecules HF (hydrogen fluoride) H2O
(water)
(-)
H
F
()
(-)
O
H
H
()
(unequal pulling)
(unequal pulling)
-Some atoms pull more strongly on the shared
electrons than other atoms do. As a result, the
electrons move closer the atom pulling harder.
This causes the atom to have a slight
____________________. -Differences in the
attractions between molecules lead to different
properties in polar and nonpolar compounds. Ex.
Water is _______________ Oil is
_________________ -Nonpolar compounds do not
dissolve well in water. This is why oil and
water ________________________.
electric charge
polar
nonpolar
don't mix