Chemical
Bonding
Three Types of Bonds
We will study . . .
Ionic Bonding
occurs between a metal
and a nonmetal
Covalent Bonding
occurs between two
nonmetals
Metallic Bonding
occurs WITHIN a metal
sample
Electron Configuration
• Remember that electron configuration
refers to the arrangement of electrons in
the orbital of an atom!
• 2
• 8
• 18
• 32
Ionic and Covalent Bonding
Video clip
• http://www.youtube.co
m/watch?v=QqjcCvz
Wwww
Chemical Bonding
• Compounds are formed from
chemically bound atoms or ions.
• Bonding involves only the valence
electrons.
Valence Electrons
•
•
Electrons are found in specific
orbits/clouds spinning around the nucleus
Valence electrons are the electrons
located in the outermost orbit
Elements become stable when:
their outer orbit contains 8 electrons or
their outer orbit becomes empty
Lewis Dot
Diagrams show the
# of Valence
Electrons
The Octet Rule
When the highest energy level of an atom is
filled, the atom is stable.
Atoms tend to gain, lose, or share electrons
until they have eight valence electrons.
Hydrogen and Helium are
the only exceptions.
Because they are so
small, they are satisfied
with two valence
electrons.
Why are the
noble gases
unreactive?
Lewis
Electron Dot Diagram
Lewis symbols show the valence
electrons as dots arranged around the
atomic symbol.
hydrogen:
H
sodium:
Na


Cl


chlorine:

Dot Diagrams
• Show the number of valence electrons
• http://hyperphysics.phyastr.gsu.edu/hbase/pertab/perlewis.html
Ionic Bonds
• form between a metal and a nonmetal
• form as a result of a transfer of electrons


Cl

Na 

• Na becomes a positive ion called = Cation
• Cl becomes a negative ion called = Anion
• Cation means “to go down”
– also think cast off
• Anion means “to go up”
– Also think accept
So, an Ion is
a Charged
Particle!!!
Ionic Bonds
What is the formula for the compound that
forms between magnesium and chlorine?



Cl



Cl


Mg

Ionic Compounds
Ionic compounds consist of a lattice of
positive and negative ions.
Ionic Compounds,
Characteristic & Properties
• High melting points
• High boiling points
• Conduct electric current when melted and
when dissolved in solution
• All of these properties are a result of the
strong attraction among ions within the crystal
lattice
Animated Reaction with
sodium and chlorine
• http://www.visionlearning.com/library/mod
ule_viewer.php?mid=55
• https://www.youtube.com/watch?v=oZdQJi
-UwYs
Naming Ionic Compounds
1) Write the name of the metal
2) Shorten the name of the non-metal and add the
suffix -ide
• KCl = potassium chloride
3) **If the Metal is a Transition Metal, after the metal
name, give its charge in Roman Numerals
• CuSO4 = Copper (II) Sulfate
Remember!!!
• Atomic symbols contain no more than 1
capital letter.
• If you see more than 1 capital letter
combined, you have a polyatomic ion.
• These, along with names, formulas, and
charges can be found on your reference
table.
Find These
• NH4
– Ammonium, +
• NO3
– Nitrate, -
• SO4
– Sulfate, 2-
Practice Naming Ionics
•
•
•
•
MgBr2
NaF
CdO
Al2O3
•
•
•
•
ZnF
Na2O
K3N
NH4NO3
Writing Ionic Formulas
• You must balance the
ions
• Same amount of (+)
as (-)
• Sodium Sulfide Na
(1+) & S (2-)
• So Na2S
• See p.173-174 in text
•
Steps:
1. write symbols
2. write charges
3. cross-over charges
from top to bottom
4. remove the charge
5. simplify numbers and
remove the 1s
Atomic Charges
• In order to write ionic formulas you have to know
these!!!! There will be a quiz on this tomorrow!
Practice
•
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•
•
•
•
•
Aluminum Oxide
Aluminum Bromide
Potassium Oxide
Sodium Chloride
Cesium Sulfide
Rubidium Fluoride
Magnesium Nitride