SOLIDS
Properties of Solids
 Definite shape and volume
 Particles are close together so attractive
forces (bonds and IMFs!) are strong
 Highly ordered
 Rigid, incompressible
Two categories of solids
 Crystalline Solids: have a regular structure in
which particles pack in a repeating pattern
from one edge of the solid to the other
 Amorphous Solids: “solids without form”
Have little structure. Includes glass and many
plastics
Crystalline Solids
 4 types of crystalline solids based on the
types of attractive forces that hold them
together.
1. Molecular solids
2. Covalent network solids
3. Ionic solids
4. Metallic solids
Molecular solids
 Composed of molecules held together by
IMFs
 Relatively soft with low melting and boiling
points
 Water, sugar, ammonia are all examples
Covalent solids
 Form crystals that can be viewed as a “giant”
molecule that is held together by an endless
number of covalent bonds
 Hard, higher melting points and boiling
points
 Diamond, graphite, quartz are examples
Graphite and diamond
Ionic solids
 Held together by the strong force of
attraction between oppositely charged ions
(cations and anions)
 Hard, brittle, high melting and boiling points
 Will conduct electricity when in aqueous
solutions but not as solids
 Salts are examples
Ionic solids
 Exist as a 3D repeating pattern called a crystal
lattice
 Many ionic solids will dissolve in water and
dissociate into ions to exist at a lower energy
Ionic Bond Strength
 A measure of the attractive forces between
the ions
 Smaller ions=stronger ionic bonds
 Fewer atom ratio=stronger ionic bonds
 Evidence comes from melting points!
 KCl has a higher melting point than KI because Cl
is smaller than I
 FeCl2 has a higher melting point than FeCl3
because there are fewer atoms
Metallic Solids
 Malleable and ductile
 Held together by “metallic bonds”
 Have their valence electrons delocalized over
many atoms
 Good conductors (mobile particles)
 “electron sea” like fruit in jello
 Examples are gold, aluminum, iron
Why are metal solids malleable
while ionic solids are brittle?
Types of crystalline solids
Type
Molecular
Attractive
Force
IMFs
Covalent
Network
Ionic
Covalent
bond
Ionic bonds
Metallic
Metallic
bonds
Example
Dry ice, sugar,
water
Diamond,
graphite
NaCl, ZnS
Au, Cu, Ag
Amorphous Solids
 No regular geometric pattern
 Jumbled up: typically long chains of
molecules that get tangled up
 Held together by IMFs
 Ex: waxes