Transcript Ionic Bonding - Johnston County Schools

Ionic Bonding
Chapter 8
Forming Chemical Bonds

Chemical bond: force that holds two atoms
together.

Ionic bonds (Ch. 8)


Covalent bonds (Ch. 9)


Transfer of electrons
Sharing of electrons
Metallic bonds (Ch. 8)

Melding of electrons (“Sea of electrons”)
Forming Ionic Bonds

Ionic bond: electrostatic force that holds
oppositely charged ions together


Transfer of electrons
Cation + Anion
Showing the Transfer of Electrons


First draw dot diagram of the two elements
making the compound (shows # of valence
electrons)
Second use the cation (metal) to fill in the
empty spaces for the anion

Remember the anion wants to have 8 valence
electrons (octet) and the cation wants to get rid
of ALL of its valence electrons.
Example 1: Sodium & Oxygen
Na
Na
O
Formula is Na2O
Example 2: Aluminum & Chlorine
Al
Cl
Formula is AlCl3
Cl
Cl
Example 3:
Magnesium & Phosphorus
Mg
P
Mg
P
Mg
Formula is Mg3P2
You Try
1.
2.
3.
Potassium & Arsenic
Barium & Sulfur
Lithium & Silicon
Naming Ionic Compounds


First name the cation (metal)
Second name the anion (nonmetal), but
change the ending to –ide

Example:




Chlorine  Chloride
Sulfur  sulfide
Arsenic arsenide
Nitrogen nitride
Examples
1.
2.
3.
4.
5.
6.
Na2O
AlCl3
Mg3P2
K3As
Li4Si
Be3N2
1.
2.
3.
4.
5.
6.
Sodium oxide
Aluminum chloride
Magnesium
phosphide
Potassium arsenide
Lithium silicide
Beryllium nitride
You Try…

Worksheet
Quick Quiz
What did we learn today?
Name: Li3P
1.
2.
3.
4.
Lithium phosphate
Lithium phosphide
Trilithium phosphide
Lithium triphosphide
25%
1
25%
25%
2
3
25%
4
Name: MgCl2
1.
2.
3.
4.
Magnesium dichlorine
Magnesium dichloride
Magnesium chlorine
Magnesium chloride
25%
1
25%
25%
2
3
25%
4
Writing Formulas for Ionic
Compounds

Instead of having to draw the electron
transfer every time….


Compounds are neutral therefore the positive
and negative charges must equal zero when
added together.
The ratio of atoms must always be the simplest
whole number ratio. (Dalton’s Atomic Theory)
Example 1

Lithium carbide




Li +1 C-4
How many Lithiums are
needed to make a
positive 4?
4
Li4C

Another way to think
about it….




Criss Cross Method
Li +1 C-4
Cross the number of the
charge over to the other
atom
Li4C (don’t write the 1)
Example 2.




Magnesium silicide
Mg+2 Si-4
You can either cross
the charges
Be careful if you
cross….Mg+2 Si-4,
does that make the
lowest ratio???

No, you have to reduce
to 2 and 1

Determine how many
+2’s will make -4
equal zero…


Answer is 2
So the formula is…
What’s the answer???

Mg2Si
Write the formula for:
Potassium nitride
1.
2.
3.
4.
KN
KN3
K3N
K3N1
25%
1
25%
25%
2
3
25%
4
Write the formula:
Aluminum sulfide
1.
2.
3.
4.
AlS
Al2S
AlS3
Al2S3
25%
1
25%
25%
2
3
25%
4
Naming Ionic Compounds with
Transition Metals

Transition metals can have varying valence
electrons and therefore have different
charges.

Ex.



Copper : Cu+1 or Cu+2
Gold: Au+1 or Au+3
We show the difference in charge by using
roman numerals to indicate the charge.
Examples.
1.
2.
CuCl
Cu3P
1.
2.
3.
3.
4.
CuO
AuCl3
4.
Copper (I) chloride
Copper (I) phosphide
Copper (II) oxide
Gold (III) chloride
Summation of the Roman Numeral
Rule

Don’t use roman numerals for:

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Zinc is always +2 and Silver is always +1
Groups 1, 2, 3 (+1, +2, +3, respectively)
Use roman numerals for:
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All other METALS!!!
You Try…

Worksheet, be careful not all of these need
roman numerals!!!!
Name: FeO
1.
2.
3.
4.
Iron oxide
Iron (II) oxide
Iron (I) oxide
Iron (III) oxide
25%
1
25%
25%
2
3
25%
4
Name: CrCl3
1.
2.
3.
4.
Chromium chloride
Chromium (I)
chloride
Chromium (II)
chloride
Chromium (III)
chloride
25%
1
25%
25%
2
3
25%
4
Name: ZnS
1.
2.
3.
4.
Zinc sulfide
Zinc (I) sulfide
Zinc (II) sulfide
Zinc (III) sulfide
25%
1
25%
25%
2
3
25%
4
Name: PbS2
1.
2.
3.
4.
Lead sulfide
Lead (II) sulfide
Lead (IV) sulfide
Lead (III) sulfide
25%
1
25%
25%
2
3
25%
4
Write the formula:
Silver phosphide
1.
2.
3.
4.
AgP
Ag3P
AgP3
AgP2
25%
1
25%
25%
2
3
25%
4
Write formula:
Manganese (IV) oxide
1.
2.
3.
4.
MnO
Mn4O
MnO4
MnO2
25%
1
25%
25%
2
3
25%
4
Write formula: calcium nitride
1.
2.
3.
4.
CaN
Ca3N2
Ca2N3
CaN2
25%
1
25%
25%
2
3
25%
4
Using Polyatomic Ions…

You write formulas and names the same
way when you use polyatomic ions, only
you don’t change the ending of the anion.

If you need more than one polyatomic ion
in the formula you have to put it in
parentheses.
You Try… Write the formula
1. ammonium hydroxide
2. potassium carbonate
3. magnesium phosphate
4. nickel (II) chloride
5. aluminum chlorate
6. calcium acetate
7. zinc permanganate
8. sodium carbonate
9. silver chromate
10. aluminum iodide
Bellwork
1.
2.
Read p. 228-229 in Blue Book
Explain why metals have the following
properties:
1.
2.
3.
Conduct electricity as solid
Malleable
Ductile
Using Polyatomic
Ions in compounds
Quick Quiz
1. Name: CaCO3
1.
2.
3.
4.
Calcium carbonate
Calcium carbide
Calcium (I)
carbonate
Calcium (I)
carbonate
100%
0%
1
2
0%
3
0%
4
2. Name: Cu2SO3
1.
2.
3.
4.
5.
Copper sulfite
Copper (I) sulfite
Copper (I) sulfate
Copper (II) sulfite
Copper (II) sulfate
48%
48%
4%
0%
1
0%
2
3
4
5
4. Formula: lithium nitrate
1.
2.
3.
LiNO3
LiNO2
Li3N
84%
12%
4%
1
2
3
5. Formula: Silver phosphate
1.
2.
3.
4.
AgPO4
Ag3PO4
AgPO3
Ag3PO3
68%
28%
4%
1
2
3
0%
4
6. Formula: Iron (III) hydroxide
1.
2.
3.
4.
FeOH
Fe(OH)3
Fe3OH
FeOH3
92%
8%
0%
1
0%
2
3
4