In This Lesson:
Ionic and Metallic
Bonding
(Lesson 3 of 4)
Today is Monday,
October 19th, 2015
Pre-Class:
Stuff You Need:
Paper Towel
Worksheet
Periodic Tables
When we were naming things like CO2 and
HNO3 and SrF2, what were all the atoms in
those compounds actually doing?
Also, take a worksheet and a paper towel.
Today’s Agenda
• Ionic and Metallic Bonds
– How ions and metals come together…
– …and stay together. Awww…
• Australian Bonding Videos
– Koalas not included.
• Where is this in my book?
– P. 194 and following…
By the end of this lesson…
• You should be able to describe the nature of
an ionic or metallic bond.
Introductory Video
• TED: George Zaidan and Charles Morton –
How Atoms Bond
Bonding Overview
• Like with Periodic Table Trends, I have a handy
way of organizing this information.
– Bonding Overview
The Types of Bonding
• There are three types of bonds out there:
• Ionic Bonds
– Metal/Nonmetal – Electrons are transferred from one
atom to another.
• Metallic Bonds
– Metal/Metal – A mixture of metals with delocalized
electrons that flow through all atoms’ shells.
• Covalent/Molecular Bonds
– Nonmetal/Nonmetal (or metalloid) – Electrons are
shared/fought over between atoms.
Ionic Bonding Video
• Australian! 1997!
Ionic Bonds
• Cations and anions are formed.
– Metals lose electrons to achieve the octet.
– Nonmetals gain electrons to achieve the octet.
• Opposite charges attract one another, forming
the bond.
• The resulting compound is neutral.
Ionic Compounds
• Crystalline solids at room temperature
– Think table salt.
• High melting points
– Takes a lot of heat/energy to melt them.
• Conduct electricity when melted or dissolved
– Electric eels in seawater.
• Finish your Bonding Overview sheets for Ionic
Bonding. Questions?
Dissociation
• In water, ionic compounds sometimes break
up into the ions of which they’re composed.
– This is a process called dissociation.
Dissociation
Bound ions in…
…component ions out.
Ca
Cl
Cl
Cl-
Ca2+
Cl-
Metallic Bonding Video
• Aluminium!
Metallic Bonds
• In metallic bonds, all the cations are packed closely
together.
• The valence electrons, rather than hanging out near
their atoms’ nuclei, exist in a sea of delocalized
electrons.
– They float around everywhere and act as a glue, like
mortar around bricks in a building.
• There is still an attraction between the free floating
electrons (-) and metal cations (+).
Metallic Compounds
• Good conductors of electricity
– Think copper wiring.
• Ductile and malleable
– Think copper wiring.
• Melting points vary
• Insoluble in water
– Cause, well, metals just don’t dissolve.
• Alloys
– Mixtures of two or more metals that have superior properties
to their components.
• Brass, bronze, steel are alloys.
• Finish your Bonding Overview sheets for Metallic Bonding.
Questions?
Ionic Lewis Dot Structures
• In order to understand ionic compounds, it
helps to be able to draw Lewis Dot Structures
for ionic compounds.
• Let’s practice using an easy ionic compound –
sodium chloride.
Ionic Lewis Dot Structures
• First, find the chemical formula for the
compound.
– Na likes to form 1+ ions, Cl likes to form 1- ions.
– Na+ and Cl- balance together in a formula as NaCl.
• Then, draw the appropriate number of electrons
in Lewis Dot form.
• Finally, “transfer” the electrons appropriately.
Na
Cl
Ionic Lewis Dot Structures
• Example: Calcium oxide
– CaO
Ca
O
Ionic Lewis Dot Structures
• Try this one: Aluminum nitride
– AlN
Al
N
Ionic Lewis Dot Structures
• Try this one: Magnesium sulfide
– MgS
Mg
S
Ionic Lewis Dot Structures
• Example: Iron (II) chloride
– FeCl2
Fe
Cl
Cl
Ionic Lewis Dot Structures
• Try this one: Cobalt (III) fluoride
– CoF3
F
Co
F
F
Ionic Lewis Dot Structures
• Try this one: Lithium oxide
– Li2O
Li
O
Li
Ionic Lewis Dot Structures
• Try this one: Silver phosphide
– Ag3P
Ag
Ag
P
Ag
Ionic Lewis Dot Structures
• Try this one: Barium nitride
– Ba3N2
Ba
Ba
N
N
Ba
Ionic Lewis Dot Structures
• Try this one: Aluminum oxide
– Al2O3
Al
Al
O
O
O
Ionic Lewis Dot Structures
• Try this one: Zinc iodide
– ZnI2
Zn
I
I
Practice
• Ionic Bonding Worksheet
– Both pages
Closure
• Try this one: Gold (III) sulfide
– Au2S3