STATES OF MATTER #1
ATTRACTIONS
1. The Van der Waals attraction (London Dispersion):
•
•
•
•
Temporary (induced) dipole – transient.
Occurs in all particles.
The major attraction in NONPOLAR substances.
BECOMES STRONGER AS MOLECULAR MASS INCREASES.
As molecular
mass
increases
CAUSES
More electrons
in the particle
CAUSES
EFFECTS OF STRONGER
ATTRACTIONS.
1. HIGHER BOILING TEMP.
2. HIGHER MELTING TEMP
3. INCREASING HARDNESS OF
SOLID STATE.
CAUSES
GREATER
temporary
polarity
CAUSES
STRONGER
INDUCED DIPOLE
ATTRACTIONS
1. The Van der Waals attraction (London Dispersion):
• VERY IMPORTANT IN NON-POLAR COVALENT SUBSTANCES
INCLUDING H2,O2,N2,Cl2,Br2,I2,F2 and CO2 and CH4.
• THE PREDOMINANT ATTRACTION IN THE METALLIC
SUBSTANCES (Au, Ag, Cu, Zn, Na etc), WHERE IT IS VERY
STRONG AS MANY METALS HAVE LARGE ATOMIC MASSES.
As molecular
mass
increases
CAUSES
More electrons
in the particle
CAUSES
EFFECTS OF STRONGER
ATTRACTIONS.
1. HIGHER BOILING TEMP.
2. HIGHER MELTING TEMP
3. INCREASING HARDNESS OF
SOLID STATE.
CAUSES
GREATER
temporary
polarity
CAUSES
STRONGER
INDUCED DIPOLE
ATTRACTIONS
THE DIPOLE ATTRACTION
1.
AN INTERMOLECULAR ATTRACTION BETWEEN THE δAND δ+ POLES OF A POLAR COVALENT MOLECULE.
2.
POLAR COVALENT SUBSTANCES HAVE PERMANANT
DIPOLAR MOLECULES, THE DIPOLE ATTRACTION IS
NOT PERMANENT.
3.
DIPOLE ATTRACTIONS ARE STRONGER THAN Van der
Waals attractions.
4.
THE STRENGTH OF DIPOLES INCREASES WITH IONIC
CHARACTER.
1. The DIPOLE-DIPOLE ATTRACTION (POLAR ATTRACTION):
•
DIPOLE-DIPOLE (POLAR or DIPOLE) ATTRACTIONS, IN
COVALENT POLAR MOLECULES that INCLUDE SO2 AND H2S.
AS IONIC
CHARACTER
INCREASES
CAUSES
GREATER
BOND
POLARITY
CAUSES
EFFECTS OF STRONGER
ATTRACTIONS.
1. HIGHER BOILING TEMP.
2. HIGHER MELTING TEMP
3. INCREASING HARDNESS OF
SOLID STATE.
CAUSES
GREATER
MOLECULAR
polarity
CAUSES
STRONGER
DIPOLE
ATTRACTIONS
THE HYDROGEN BOND ATTRACTION
1. A VERY STRONG DIPOLE ATTRACTION THAT OCCURS WHEN H IS
BONDED TO F,O,N IN AN ASYMETRICAL MOLECULE.
2. IT IS NOT A TRUE BOND.
3. IS UNUSUAL IN THAT IT HAS A BOND LENGTH, CAUSES H2O TO
EXPAND ON FREEZING.
4. BECOMES STRONGER WITH INCREASING IONIC CHARACTER OF
THE MOLECULE.
IONIC
CRYSTAL
LATTICE
H-BOND
BETWEEN
δ- AND δ+
THE δ- OF
OXYGEN
THE δ+ OF H
ATTRACTS TO A – ATTRACTS
TO A + ION
ION,
The white arrows
represent Hbonds which:
-order the
molecules into a
crystal formation.
-cause spacing
between the
molecules in the
solid phase –
causes
expansion of ice..
H BOND ATTRACTION
δ+
δ+
H
δ+
H
δ+
H
OXYGEN
δδ+
δ+
H
H
δ+
H
δ+
H
H
OXYGEN
OXYGEN
δ-
δδ+
δ+
H
H
δ+
δ+
H
H
OXYGEN
OXYGEN
OXYGEN
δ-
δ-
δ-
MOLECULE TO ION ATTRACTION
ATTRACTION
THE
MOLLECULE
TO ION
ATTRACTION
BETWEEN
THE δ+ OF
THE
HYDROGEN
POLE OF
WATER AND
THE – ION.
- ION
δ+
δ+
H
H
OXYGEN
δ-
MOLLECULE
ION
ATTRACTIONS
ARE VERY
STRONG AND
HARD TO
BREAK,
MAKING THE
SEPARATION
OF WATER AND
SALTS
CONSUME
LARGE
AMMOUNTS OF
ENERGY.
δ+
δ+
H
H
OXYGEN
δ-
+ ION
THE
MOLLECULE
TO ION
ATTRACTION
BETWEEN
THE δ- OF
THE OXYGEN
POLE OF
WATER AND
THE + ION.
ELECTROSTATIC (IONIC) ATTRACTION
• Electrostatic ATTRACTIONS STTRACT POSITIVE IONS TO
NEGATIVE IONS IN A CRYSTAL LATTICE SOLID WHERE:
– THE IONS CANNOT MOVE AND THUS CANNOT CARRY A CHARGE
(CONDUCT).
– THE ATTRACTIONS ARE SO STRING THAT THE CRYSTAL IS HARD
AND BRITTLE WITH VERY HIGH MELTING AND BOILING POINTS.\
– WHEN THE IONS DISSOLVE IN WATER, THEY CAN CARRY A
CHARGE.
Na+
Cl-
The lines represent the
electrostatic attraction.
Notice the ions are in a
regular, predicable
geometrical arrangement.
There is no randomness
(LOW ENTROPY)
Fracture planes of ionic crystals, brittleness.
ORDERING OF MELTING AND
BOILING POINTS
INCREASING MELTING AND BOILING POINTS 
NON-POLAR
COVALENT
POLAR
COVALENT
- Order based on
molar mass.
- Order based
IONIC
METALLIC
- Order based on
on ionic
character
ORDER
METALS
BASED ON
MASS
ionic character
COVALENT
NETWORK
SiO2
C(s)
diamond