Chapter 15
Ionic Bonding and Ionic
Compounds
What is an Ionic Bond?
Ionic Bond

Bond formed between a metal and
nonmetal.
Why do atoms bond?
Atoms bond in order to acquire a full set
of valence electrons.
 Most of the time this is 8 . This is known
as the octet rule.
 Atoms will gain, lose or share in
order to attain a full set of electrons

Valence Electrons
 The
electrons responsible for the
chemical properties of atoms are
those in the outer energy level.
These electrons are called the
valence electrons.
 Valence electrons - The electrons
in the outer energy level
Electron Configuration
Electron Configuration…
Maybe you learned it this way
Electron Configurations for
Cations
Metals lose electrons to attain noble
gas configuration.
 They make positive ions (cations)
 If we look at the electron configuration,
it makes sense to lose electrons:
 Na 1s22s22p63s1 1 valence electron
 Na1+ 1s22s22p6 noble gas configuration

Electron Configurations for
Anions
Nonmetals lose electrons to attain noble
gas configuration.
 They make negative ions (anions)
 If we look at the electron configuration, it
makes sense to lose electrons:
 F 1s22s22p5
2 valence electrons
 F-1 1s22s22p6
noble gas configuration

Keeping Track of Electrons
Atoms in the same column...
– Have the same valence electrons.
 LABEL! 

Bohr Model of the Atom
The Bohr Model has an atom consisting
of a small, positively-charged nucleus
orbited by negatively-charged electrons.
• 1st shell: 2 electrons
• 2nd shell: 8 electrons
• 3rd shell: 18 electrons
Example: Bohr Model of
Nitrogen
CHEM-IS-TRY
Draw the Bohr Model of Fluorine
Electron Dot diagrams
A way of keeping track of
valence electrons.
 How to write them?
 Write the symbol.
 Put one dot for each
valence electron
 Don’t pair up until they
have to (Hund’s rule)

X
The Electron Dot diagram for
Nitrogen
Nitrogen has 5 valence
electrons.
 First we write the symbol.
Then add 1 electron at a
time to each side.
Until they are forced to pair up.

N
Write electron dot diagrams:
 Na
 Mg
C
O
Properties of Ionic Compounds
A
regular repeating arrangement of
ions in the solid: this is known as a
lattice. Structure is rigid.
 High melting points
Crystalline structure
Do they Conduct?
Conducting electricity is allowing charges
to move.
 In a solid, the ions are locked in place.
 Ionic solids are insulators.
 When melted, the ions can move around.
Therefore, they have the ability to conduct
electricity
 Ionic Compounds dissolved in water
conduct

Completing the Circuit