Ionic Bonding

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Ionic Bonding

• Mr. Thomson
• Experience Academy

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Classifying Pure Substances
http//wps.prenhall.com/wps/media/objects/476/4883
16/Instructor_Resources/Chapter_05/FG05_07.JPG
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Comparison Bond Types
http//www.elmhurst.edu/chm/vchembook/images/150c
ompare.GIF
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Ionic Bonding

• Ionic Bond Attraction between positive and
  negative ions that holds atoms in place in an
  ionic compound (usually a crystal).
• Ionic compounds usually form when a metal
  positive ion (cation) bonds with a non-metal
  negative ion (anion).
• Ionic compounds involve the transfer of
  electrons. (Unlike covalent bonding, where
  electrons are shared.)

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Crystal Structure of Ionic Compounds

• Ionic compounds do not form molecules. Instead,
  ionic compounds form an organized
  three-dimensional structure of alternating
  positive and negative ions.

http//www.mtl-system.com/Web20Images/Model_chemi
stry/Large/Molecular20Model/T22003_l.jpg
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Comparison Molecules and Ionic Compounds
http//www.physchem.co.za/Bonding/Molecule.htm
Water, a molecular compound, is made of billions
and billions of INDIVIDUAL water molecules.
Salt, an ionic compound, is made of billions and
billions of ions, all together in a crystal
lattice. There are NO individual molecules of
NaCl.
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How are ions formed?

• When atoms form ions, they lose or gain electrons
  in order to have eight valence electrons.

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How is sodium chloride formed?

• Animation (Source http//www.bios.niu.edu/sims/
  chemistry/Chemistry3.htm)

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Na Cl

• Na 1s22s22p63s1
• Remember the rule of eight. Sodium wants a
  full outer (valence) shell. So sodium can either
  gain seven electrons to fill the third shell, or
  get rid of the 3s1 electron. Then the outer
  shell (second) will be full. The new electron
  configuration will be
• Na 1s22s22p6

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Na Cl

• Na 1s22s22p6
• Why is sodium 1 when it loses an electron?
• Na Na
• p 11 p 11
• e- 11 e- 10
• Zero charge 1 charge

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Na Cl

• Cl 1s22s22p63s23p5
• Remember the rule of eight again. Chlorine
  wants a full shell also. So it can either lose
  seven electrons, or gain one electron. The new
  electron configuration will be
• Cl - 1s22s22p63s23p6

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Na Cl

• Cl - 1s22s22p63s23p6
• So why is chlorine -1 when it gains an electron?
• Cl Cl -
• p 17 p 17
• e- 17 e- 18
• Zero charge -1 charge

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Sodium Chloride
Na
Cl
-1
1
Na
Cl
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Crystal Structure of Sodium Chloride
Source http//www.geog.ouc.bc.ca/physgeog/conten
ts/images/sodiumchloride.jpg
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Another Look at Sodium Chloride Crystal
http//library.tedankara.k12.tr/chemistry/vol1/sal
ts/trans19.htm
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Na Cl

• In all ionic compounds, the charges cancel, so
  the overall charge for the compound is zero.

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Predicting Formulas for Ionic Compounds
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Magnesium sulfide

• Mg S
• Ne3s2 Ne3s23p4

Mg
S
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Magnesium sulfide

• Mg S
• Ne3s2 Ne3s23p4

Mg
S
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Magnesium sulfide

• Mg S
• Ne3s2 Ne3s23p4

-2
2
Mg
S
Extra Electrons from Magnesium
Mg 2 S -2 Ne Ne3s23p6
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Magnesium sulfide
Mg 2 S -2 Ne Ne3s23p6 MgS
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Calcium chloride

• Ca 2 Cl -1
• CaCl2
• When the charges dont cancelcross the charges
  to write the correct formula.

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Aluminum Oxide

• Al 3 O -2
• Al2O3
• When the charges dont cancelcross the charges
  to write the correct formula.

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Polyatomic Ions

• Polyatomic ions a charged group of covalently
  bonded atoms. The charge comes from gaining or
  losing electrons as a group. (See back of your
  periodic table.)
• Examples
• Ammonium NH4
• Nitrate NO3-

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Sodium nitrate

• Na 1 NO3 -1
• Do the charges cancel?
• Yesso just write the formula.
• NaNO3

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Potassium carbonate

• K 1 CO3 -2
• Do the charges cancel?
• Noso cross the charges.
• Answer K2CO3

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Ammonium sulfate

• NH4 1 SO4 -2
• Charges cancel?
• Noso cross the charges.
• (NH4)2SO4

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Calcium Phosphate

• Ca 2 PO4 -3
• Charges cancel?
• Noso cross the charges.
• Ca3(PO4)2

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Classwork

• Homework
• Naming Ionic Compounds WS 1
• Ionic Bonding Classwork
• Both Stamped Tomorrow
• Many of you still need to finish the Molecule
  Building Activitythis will need to be completed
  on your own time Many of you also still need to
  turn in your Online Bonding Activity.