South Pasadena • Honors Chemistry
Name
10 • Bonding
Period
10.3
Date
NOTES
–
SOLIDS
Types of Solids – Substances with extremely high melting point temperatures are held together by very strong
inter-particle forces, so they are solids at standard state (25°C).
Substances with lower melting point temperatures are held together by
much weaker inter-particle forces, and exist in solid, liquid or gas states.
Crystalline Solids – Solids that have regular repeating arrangements of
particles. Their vertices of a crystalline solid are called lattice points.
Amorphous Solids – No repeating arrangement of particles. E.g. glass.
Four Types of Crystalline Solids – classified based on types of inter-particle forces
(1) Ionic solids
(2) Metallic solids
(3) Network covalent solids
(4) Molecular solids



Ionic solids
o Repeating units of alternating cations and anions held together by strong
ionic bonds.
o We represent one neutral ionic unit in its formula (e.g. NaCl), they do not
exist as molecules.
o Ionic solids tend to be hard and brittle.
o Ionic substances do not conduct electricity as solids, but many ionic solids
can dissolve in water into individual ions and these solutions conduct
electricity. Also, ionic substances, when melted (its liquid form is called
molten), also conduct electricity, as ions move freely.
Metallic solids
o Repeating units of metal cations held together by metallic bonds.
o Since metals tend to lose electrons, these mobile electrons are delocalized
among the metal atoms, forming a sea of electrons. This movement of
electrons allow metals to be ductile and malleable, be lustrous, and be
good electrical conductors.
o Alloys are mixtures of metals, such as bronze (Cu and Sn), steel (Fe and C), and brass (Cu and Zn).
Network covalent solids
o Repeating units of non-metal atoms held together by strong covalent bonds.
o Network covalent solids in general tend to be very hard and do not conduct electricity.
o Limited examples: graphite, diamond, and silica.
 Graphite is a solid made of layers of carbon atoms covalently bonded in trigonal planar
arrangements with other carbon atoms. Unlike other network covalent solids, graphite has loose
unbonded electrons and conducts electricity fairly well. It is fairly soft and is a good lubricant. A
single layer of graphite called graphene.
 Diamond is a solid made of carbon atoms covalently bonded in tetrahedral arrangements with other
carbon atoms. It is extremely hard and abrasive, and is an excellent electrical insulator.
 Silica, or silicon dioxide (SiO2), is found in nature as quartz, as well as in synthetic materials such as
silica gel.
graphite
diamond
silica

Molecular solids
o Repeating units of molecules of covalent compounds held together
by weak inter-molecular forces.
o They melt or vaporize easily and are often in liquid or gas states.
They tend to be brittle and electrical insulators.
Type of Solid
Ionic
Lattice Unit
Inter-particle forces
Examples
Conductivity
Hardness/Brittleness
Network Covalent
Molecular
Cations and anions
Metal cations
Non-metal atoms
Molecules of
Covalent Compounds
Ionic Bonds
Metallic bonds
(Sea of electrons:
mobile e– delocalized
among metal atoms)
Covalent Bonds
Inter-molecular
Forces
NaCl, AgNO3, Fe2O3,
CaCl2
Cu, Zn, Ag, Fe,
bronze (Cu+Sn),
steel (Fe+C),
brass (Cu+Zn)
Cdiamond
Cgraphite
Silica (SiO2), quartz
C12H22O11 (sugar),
H2O, CO2, Cl2, Ar,
organic molecules
High
500°C-3000°C
High
1600°C-3800°C
Low
< 200°C
Conductor as solid
Insulator, except
graphite
Insulator
High
200°C-2500°C
Conductor in aqueous
solution and as
molten liquid
Melting Point
Metallic
Hard and brittle
Malleable/ductile Very hard and brittle,
Less hard, but brittle
(also lustrous/shiny) except for graphite
Inter-Molecular Forces (IMFs) –
weak attractions between molecules,
also called Van der Waals forces.
These are different from bonds, which
are strong intra-molecular forces
(attractions within molecules).
IMF
London Dispersion Forces

Molecules



Energy
Example
Dipole-Dipole Interactions
Very weak temporary

attractions between
molecules caused by the
movement of electrons.

Electrostatic attraction between
In all molecules due to

opposite poles of polar
polarization of molecule due
compounds.
to shifts in e– cloud.
Significant in non-polar
compounds
More e– = stronger LDF
0.5-40 kJ/mol
5-25 kJ/mol
Cl–Cl……Cl–Cl
δ+
δ–
δ+
……
H–Cl
δ–
H–Cl
Hydrogen Bonding
Hydrogen atom tethered
between adjacent N, O, or F
(small, highly EN atoms).
Not a bond, despite its name
Explains the unique
properties of water,
responsible for structures of
biological compounds
(e.g. structures of proteins
and nucleic acids).
10-40 kJ/mol
δ+
δ–
δ+
……
H–F
δ–
H–F