Covalent Bonding
 Atoms
Covalent Bonding II
can also bond by
sharing more than 1 pair of
electrons
 Atoms can also form:
 double
bonds
 triple bonds
Covalent Bonding
 Double
4
e-,
2 pairs
 Triple
6
e-,
bonds
bonds
3 pairs
 Double
and triple bonds are
called multiple bonds
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Covalent Bonding
far, all of the multiple bonds
that we have looked at were in
diatomic molecules
 Multiple covalent bonds can also
exist in molecules containing
atoms of different elements
Covalent Bonding
 So
2 double bonds in the CO2
molecule are identical to each
other
 The
Coordinate Covalent Bonds
Covalent Bonding
oxygen attains an octet with
the creation of a double bond, but
the carbon doesn’t!
 The problem is solved if the
oxygen also donates an additional
unshared pair to the double bond,
forming a triple covalent bond
 The
Coordinate Covalent Bonds
Coordinate Covalent Bonds
coordinate covalent bond is a
covalent bond in which 1 atom
contributes both electrons in a
pair that are shared
 In a coordinate covalent bond, a
shared pair comes from only 1 of
the two atoms sharing them
A
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Coordinate Covalent Bonds
Coordinate Covalent Bonds
ammonium ion [NH4]+ is
formed from the ammonia
molecule (NH3) by the addition of
an [H]+ ion
 NH4+ contains 4 covalent bonds:
 The
‘standard’ covalent bonds
 1 coordinate covalent bond
3
Polyatomic Ions
 NH4+
is an example of a
polyatomic ion
 A polyatomic ion is a molecule
that has a charge (table E)
 Polyatomic ions always contain at
least 1 coordinate covalent bond
Polyatomic Ions
polyatomic ions can be cations
or anions, they can participate in
ionic bonding with another ion of the
opposite charge!
 Ionic compounds containing
polyatomic ions contain both
covalent and ionic bonds
 Since
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