4.8 THE STRUCTURE AND PROPERTIES OF SOLIDS
*Amorphous solids:
 solids whose constituent particles are ________________ arranged and have ___ ordered long-range structure
*Crystalline solids:
 solids whose atoms, ions, or molecules have an _______________ arrangement extending over a long range
Types of Crystalline Solids
*In all types of bonding, we can consider a solid as a lattice of particles. The type of bonding depends on the
type of particle and the forces that exist between them.
1) Ionic Crystalline Solids
 The attractive force between oppositely charged ions. The lattice is made of _______________ charged ______. Salts
are ______________. SALTS ARE NOT ____________________!
 e.g. NaCl – A crystal of sodium chloride is composed of alternating _____ and ____ ions ordered into a regular threedimensional arrangement held together by _________ bonds.
*Why do ionic compounds shatter…if they are hit with a hammer, for
example?
Conductivity: How do ionic substances conduct? In what state must they
be in?
2) Covalent – Giant/Network Crystalline Solids
 Regular ________________ bonds, but they exist between _________ atoms in a giant three-dimensional array – that
is, every atom is covalently bonded to all its nearest neighbours. In effect, a covalent network is one very large molecule.
Some Examples of Covalent Networks (all with “diamond” structure):
*SiO2 (silica/quartz)
*Silicon
Silicon Carbide (a.k.a. moissonite)
1
Allotropes of Carbon – Graphite, Diamond and Fullerene (giant covalent network solids)
*Allotropes are different molecular or crystalline forms of the _____________element that differ in _______________
and ________________ properties.
Diamond
__________ – all electrons are
used in localized bonds
Graphite
________ – only ___ electrons
from each carbon are used in
bonding – the fourth electron is
found in a ________________
pi cloud …formed by
unhybridized ___ - orbitals
Fullerene
_____________ – surface of the
“ball” is conductive, but imagine
an ant running across the surface
of a lot of basketballs
Geometry
3-dimensional ____________
arrangement of carbons
“2-dimensional”…layers of
__________ of carbon
“2-dimensional”, large (C60),
______________ molecules
Hardness
Very ________ – all atoms are
held together in the lattice by
strong ___________ bonds
Very _______ –
_________
2 - dimensional sheets slide over
each other because of weak ____
____ _______’ forces between
the sheets
Conductivit
3) Covalent – Molecular Crystalline Solids
CO2(s)
 Regular covalent bonds, but the atoms form little “packages” called _________________. Each
“package” is held together by strong _____________ bonds; however, they are attracted to each other by
weak __________________forces such as ________________, ________________or
_________________.
 Examples include:
Sucrose [C12H22O11(s)], ice[H2O(s)], carbon dioxide[CO2(s)], iodine[I2(s)] and sulfur[S8(s)].
Remember: A change of state is NOT a ______________ reaction. It is a physical change.
Examples:
H2O(s) -------------------
C2H5OH(s) ----------------
CO2(s) ------------------------
C12H22O11(s) ----------------
4. Metallic Crystalline Solids
 Metallic crystals such as silver, lead, aluminum, or iron are like covalent network solids, but they
consist of metal atoms.
 Kept together by ___________ bonds – (i.e. the electrostatic attraction between a lattice of positive
_______________ _______and a “sea” of _____________ valence electrons that moves among them)
 In general, the strength of the metallic bond increases when the charge on the cation ____________
and the number of valence electrons, participating in metallic bonding, also _____________.
 Metals are:
1) malleable  can be hammered into ___________; and, ductile  can be molded into ___________
*Why are metals malleable and ductile while ionic crystals are brittle? (How does the ionic crystal differ
from the metallic crystal?)
2) excellent _______________ of _______________ *Why?
*Metals are excellent conductors due to the presence of ________________________ electrons. They are able to conduct
in BOTH the _________________and ________________ state.
2
Summary:
Solid
Ionic
Lattice Forces
Boiling Point
Metallic
Giant Covalent Networks
Molecular Covalent
Practice Questions:
1. Identify the main type of bonding and the type of solid for each of the following:
Solid
SiO2
Type of Bonding
Type of Solid/Crystal
Na2S
CH4
C
Cr
CaO
SiC
Fe
PCl5
2. Match the solids, NaBr(s), V(s), P2O5(s), and SiO2(s), to the property listed below.
a)
high melting point, conducts electricity …………………………______________
b)
low melting point, soft……………………………………………______________
c)
high melting point, soluble in water………………………………______________
d)
very high melting point, nonconductor…………………………...______________
3