Other bonding
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Metallic bonding
…
holds atoms of metallic elements to each
other.
 …is similar to LD forces (e¯ of one atom
attracted to p+ of neighbouring atoms).
 Valence e¯ are very loosely held by the atoms in
metals, so they move freely in the metal.
 This also explains electrical conductivity (freely
moving e¯).
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Metallic b.p.
Metallic
bonding is very strong.
It results in the relatively high b.p. for
metallic elements.
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Network covalent bonding
A unique
bond where an atom has very
strong bonds in multiple directions to other
atoms around it.
Know these examples:
diamond (Cn)
silicon carbide (SiC)
silicon dioxide (SiO2)
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Ex. diamond
Each C atom bonds to 4 C atoms around it.
In a sense, a diamond is a single HUGE molecule.
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Network covalent b.p.
These
substances have extremely high
boiling points.
Ex: diamond boils at 4827°C
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Ionic bonding
…
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
is both intra and intermolecular.
Around an ion
Each
ion is surrounded by ions of the
opposite charge.
A Cl¯ ion is bonded to several Na+ ions
around it.
An NaCl does not exist by itself.
∴ ionic bonding is both inter and
intramolecular.
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Ionic b.p.
Strong
ionic bonding results in very high
b.p.
Ex: NaCl b.p. = 1465°C
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Ranking forces
High
Low
covalent
ionic
intramolecular
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
metallic
LD
HB
intermolecular
dd
Example
Rank
the following in order from highest to
lowest boiling points:
C8H17OH, C6H11F3, Cn, C9H18, CaCO3,
C7H14(OH)2, Zn, CCl4
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Do “other” bonding first
1.
Cn (network covalent is always the
highest b.p.)
2. CaCO3 (ionic)
3.
Zn (metallic)
Rank remainder using a chart.
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
Fidler Aaron
Wednesday, June 6, 2012 1:07:40 PM MT
# e¯
LD Rank
(high = 1)
dd
HB
b.p. rank
(high = 1)
C8H17OH
74
1
√
√
5
C6H11F3
74
1
√
X
6
C9H18
72
2
X
X
8
C7H14(OH)2
74
1
√
√√
4
CCl4
74
1
X
X
7