Warm up
10-22-15
1. Name the following compounds:
CaCl2
S2F5
2. Write the chemical formula for these compounds
Potassium sulfide
Diphosphorus tetrachloride
Agenda
Homework
Turn in lab bonds
Take Quiz Unit 4
Notes Unit 4-4
Practice WS Unit 4-4
Oct 24 – Academic School
Oct 29 - Extra credit due
Oct 30 - Online HW unit 4
Quiz Unit 4
2 questions - Finding Ions
(positive and negative charge)
2 questions - Bonds (3 types)
2 questions - Naming compounds (rule 1 & 2)
You will need a half sheet of paper
Record your quiz version #
Unit 4-4
Lewis Dot structure
How do we determine which
elements will combine to make
bonds?
Nomenclature: Ionic Compounds
Transition Metal Examples
Regular metal
1.
2.
3.
4.
CaCl2 = Calcium chloride
Na2S = Sodium sulfide
FeCl2
FeN
Iron (I) nitride
Iron (II) nitride
Answers
1. Iron (II) chloride
2. Iron (III) nitride
3. Fe3N
4. Fe3N2
Nomenclature: Ionic Compounds
Polyatomic Ions
(NH4)+
(OH)(CO3)-2
(NO3)(SO4)-2
(PO4 )-3
(Cr2O7)-2
Ammonium
Hydroxide
Carbonate
Nitrate
Sulfate
Phosphate
Dichromate
(NH3)
Ammonia
(NO2)(SO3)-2
(PO3)-3
Nitrite
Sulfite
Phosphite
Naming Polyatomic Ions Examples
1.
2.
3.
4.
______________
Strontium sulfate
Calcium nitrite
______________
Ammonium Sulfide
Potassium hydroxide
SrSO4
Ca(NO2)2
(NH
4)2S
_____
KOH
_____
Naming Ionic Compounds
Practice
1.
2.
3.
4.
5.
6.
7.
8.
______________
______________
Lithium Bromide
Calcium Fluoride
____________
Iron (III) Phosphide
______________
______________
AlCl3
Na2S
_____
_____
CuCl2
Transition
metal
____
Li3PO4
Sr(NO3)2
Electron
Distribution in
Molecules
G. N. Lewis
1875 - 1946
• Electron distribution is
depicted with Lewis
structures (electron
dot) showing valence
electrons
• Show the number of
bond in the covalent
compound
(In ionic bonds, it
was decided with
charges)
Lewis Structures for Elements
1) Write the element symbol.
2) Starting at the right, draw
4 electrons, or dots, one
on each side around the
element symbol.
Lewis Structures
Try these elements on your
own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Lewis Structures
On your worksheet, try
these elements on your own:
a)
b)
c)
d)
e)
f)
H
P
Ca
Ar
Cl
Al
Bond Formation
A bond can result from an overlap of
atomic orbitals on neighboring atoms.
••
H
+
Cl
••
••
•
•
H
Cl
••
•
•
••
H Cl
Note that each atom has a single, unpaired electron.
••
•
•
Bond and Lone Pairs
• Valence electrons are distributed as
shared or BOND PAIRS and unshared
or LONE PAIRS.
••
H
•
•
Cl
•
•
••
shared or
bond pair
lone pair (LP)
This is called a LEWIS structure.
Sharing Electrons
• All atoms want to have 8 valence electrons
(except H, only needs 2)
• Obtain a total of 8 by sharing
• Only lonely electrons will share – pair of
electrons with existing partners will not share
and make bonds
Types of Bonds
Single bond
Cl2
Double bond = CO2
Triple bond
N2
Example Lewis Dot
for Compounds
Draw CH4
Draw C2H4
Draw H2O2
Valence Shell Electron Pair Repulsion
(VSEPR)
• Lewis structure help predict molecular shape
Assignments
• Summary
• Lewis dot worksheet (4-4) due next class