2. Kinetic Molecular Theory of Liquids and
Solids
■ Liquids and solids are condensed states.
■ Liquids
– Have definite volume and assume the
shape of its container
– Much denser than gases
– Are more difficult to compress than
gases
– Molecules
■ are close together
■ little of empty space between
molecules
■ are held together by attractive
intermolecular forces
■ are in constant motion
■ Move/slide one past another freely
so liquid can flow
3. Kinetic Molecular Theory of Liquids
and Solids
■ Solids
– Almost uncompressible
– Definite shape and volume
– Most solids are denser than liquids
– Particles
■ are more closely packed than in
liquids
■ are arranged in highly organized
order
■ Are always in constant motion
■ vibrate around fixed locations
■ Held together by strong
intermolecular forces.
4.
5. Structure of Solids
■ Most of solids are
crystalline.
■ Particles are arranged in an
orderly, repeating, three-
dimensional pattern.
■ The shape of the crystal
depends on the
arrangement of the
particles within it.
■ The smallest group of
particles within the crystal
that retains the geometric
shape of the crystal is
called a unit cell.
■ A crystal lattice is a
repeating pattern of unit
cells.
9. Intermolecular Forces (IMF)
■ Are attractive forces between molecules
■ Are much stronger in liquids and solids than in
gases.
■ The more polar molecules are the stronger
intermolecular forces are.
■ Strength of intermolecular forces determines the
state of matter.
■ Energy is required to break IMF and change
states of matter.
■ Melting and boiling points of any substance
depend on strength of IMF in the substance.
10. Strength of Intermolecular Forces
(IMF)
■ Metallic bond (in metals)
■ Ionic bond (in ionic compounds)
■ Hydrogen bond (in water and
some other compounds)
■ Van der Waals forces (dipole-dipole, dispersion)
– Interaction between partial charges in polar
covalent molecules
– The more polar molecules are the stronger
intermolecular forces are.
Strengt
h
11. Metallic Solids/Metallic Bond
■ Metallic solids are
composed of metal
atoms that are held
together by metallic
bonds.
■ The electrons in metallic
solids are delocalized.
■ It means that valence
electrons move freely
between metallic
cations.
■ A good picture of a
metal solid is that of
cation in a sea of
electrons.
14. Phase Changes
■ Vaporization is the process in which liquid is transformed
into a gas.
■ Condensation is the process by which a gas or a vapor
becomes a liquid
■ Melting (fusion) is the process of solid becoming a liquid.
■ Freezing (solidification) is the process when a liquid
becomes a solid.
■ Sublimation is the change of substance from a solid to a
vapor without passing through the liquid state.
■ Deposition is the process by which a gas or a vapor turns
straight into a solid.
