Download (ionic or covalent).

Catalyst – October 6(4), 2012
WAY BACK WEDNESDAY!
1.
2.
What is the mass of an atom that has 14
protons and 15 neutrons?
The reaction of baking soda and vinegar at 25
degrees Celsius produces gaseous carbon
dioxide for 1 minute. Which of the following do
you think will happen if you react baking soda
and vinegar at 50 degrees Celsius?
a)
b)
c)
d)
Less gas will be produced
Gas will be produced for more than 1 minute
The reaction will have a strong odor
The reaction will not occur
Today’s Agenda
Catalyst
 Electronegativity Difference, Bond
Type, and Bond Polarity
 Work Time
 Speed Dating???
 Exit Question

HW: Study for Test!
Today’s Objectives
SWBAT determine bond type using
electronegativity differences (∆EN).
 SWBAT classify compounds as ionic or
covalent, describe characteristics, and
write names and formulas correctly.
 SWBAT get ready to DOMINATE the
Test tomorrow!!!!

NOTES TITLE:
ELECTRONEGATIVITY
DIFFERENCE
AND BOND TYPE
How to tell ionic and covalent apart

Key Point #1: Along with looking
at the formula and name for a
compound, we can also look at
electronegativity differences (∆EN)
in order to determine bond type
(ionic or covalent).
Electronegativity Differences

We can also look at electronegativity differences
(∆EN)
 Look
at Electronegativity Chart to find element
electronegativities
 Find the difference by using subtraction
 Look at Bond Type Chart to determine bond types
Electronegativity
Chart
Remember…
Electronegativity is an atom’s ability to
attract electrons to itself in a chemical
bond
 Electronegativity is expressed in numerical
values of 4.0 or less

These
numerical values are called Paulings
Higher number means the atom will attract
electrons more strongly
Electronegativity Chart
Pauling Values
Bond Polarity
Key Point #2: Bond polarity is based on
differences in electronegativities of
atoms forming a bond.
As electronegativity difference (∆EN)
increases, polarity of bond increases
Bond Polarity Terms to Know
Pure Ionic = Complete transfer of
electrons from one atom to another
 Polar Covalent = Unequal sharing of
electrons between two atoms
 Nonpolar Covalent = Equal sharing
of electrons between two atoms

Pure Ionic Bonding

Total give and take (transfer) of electrons! = Big ∆EN!
I have no
chance!
Covalent Bonding is like a Tug-of-War

The more electronegative atom will pull
electrons harder
Polarity and Electronegativity

Polar Covalent electrons are pulled
more toward one of the
atoms

Nonpolar Covalent electrons are shared
equally between atoms
Low ∆EN!
Big ∆EN!
Big Dog – Little Dog
Medium Dog – Medium Dog
Polarity Ranges
Key Point #3: Bonds are not
always purely ionic (I) or
purely covalent (NPC). They
could be slightly ionic (VPC) or
slightly covalent (MPC).
How to Calculate Electronegativity
Difference (∆EN)
1. Using Electronegativity Chart, find
Pauling values for each element
2. Subtract the smaller number from the
bigger number
Example: 4.0 (F) – 0.9 (Na) = 3.1
3. Look at Bond Type Chart to
determine bond polarity
Bond Type Chart – Copy into notes!
∆EN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic
Example 1

Determine the type of bond in LiBr
1.
Find electronegativity of each atom
Electronegativity Chart
Example 1

Determine the type of bond in LiBr
1.
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings
Example 1

Determine the type of bond in LiBr
1.
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings
2.
Find Electronegativity Difference (∆EN)
DEN = 3.0 – 1.0 = 2.0
3.
Look at chart to determine bond type.
Bond Type Chart
DEN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic
Example 1

Determine the type of bond in LiBr
1.
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings
2.
Find Electronegativity Difference (∆EN)
DEN = 3.0 – 1.0 = 2.0
3.
Look at chart to determine bond type.
Bond Type: Ionic
Example 2

Determine the type of bond in O2
1.
Find electronegativity of each atom
Electronegativity Chart
Example 2

Determine the type of bond in O2
1.
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings
Example 2

Determine the type of bond in O2
1.
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings
2.
Find Electronegativity Difference (∆EN)
DEN = 3.4 – 3.4 = 0
3.
Look at chart to determine bond type.
Bond Type Chart
DEN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic
Example 2

Determine the type of bond in O2
1.
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings
2.
Find Electronegativity Difference (∆EN)
DEN = 3.4 – 3.4 = 0
3.
Look at chart to determine bond type.
Bond Type: Nonpolar Covalent
How Polar Is It?

Determine the polarity of each bond in the
following compounds by calculating the
electronegativity difference for each:
CO
2. AlP
3. N2
1.
4. HF
5. CaO
6. H2
Electronegativity Chart
Bond Type Chart
Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
0.9 – 1.69
Moderately Polar
Covalent
Very Polar Covalent
1.7 or greater
Ionic
Practice Time!

Please finish the worksheet
Exit Question
Write one thing you will do
today/tonight to get ready to
DOMINATE the Test tomorrow.
 Then doooo it!

Exit Question
Magnesium is a metal. Sulfur is a nonmetal.
1. What type of bond is formed between
these elements?
2. Describe two ways that you could use
to determine your answer to number 1.
HW: Review Chapter 12,
Review Sheet, STUDY!
Catalyst – September 23+6, 2011
1.
2.
3.
What is a cation?
What bond shares electrons?
Complete the analogy:
Opposite is to ionic as __________ is
to covalent.
Today’s Agenda
Catalyst
 Project Work Time
 Speed Dating
 Exit Question
HW: Unit 3 Practice Test
Questions (Half-Sheet)

Today’s Objectives
SWBAT complete AWESOME
Chemistry.com Projects.
 SWBAT find love in Speed
Dating!

Speed Dating
Half of you will remain STATIONARY
 Half of you will rotate IN ORDER,
CLOCKWISE
 You will have 4 minutes with each “date”
 Ask each other questions to determine if
your atoms have a potential love match!

Exit Question
Catalyst – September 5(6), 2011
FUN GRAPH FRIDAY!

What are TWO
questions you
could ask when
looking at this
graph?
Today’s Agenda
Catalyst
 HW Review
 Ionic vs. Covalent Lab!
 Do Gatorade or Powerade Conduct
Electricity?
 Group of the Week
 Exit Question

Today’s Objectives

SWBAT conduct an experiment to
determine if unknown substances are
ionic or covalent.
Today’s Lab
Safety: Be careful with hotplates. Be
Goggle Gangsters!
 Alternate between heating and
conductivity tests

Unknown Substances
A:
 B:
 C:
 D:

Salol
Sodium Chloride (Salt)
Copper (II) Sulfate
Sucrose (Sugar)
Salol
Chemical Name: Phenyl salicylate
 Chemical Formula: C13H10O3
 Melting Point: 41.5˚C

Sodium Chloride (Salt)
Chemical Name: Sodium Chloride
 Chemical Formula: NaCl
 Melting Point: 861˚C

Copper (II) Sulfate
Chemical Name: Copper (II) Sulfate
 Chemical Formula: CuSO4
 Melting Point: 110˚C

Sucrose (Sugar)
Chemical Name: Copper (II) Sulfate
 Chemical Formula: C12H22O11
 Melting Point: 186˚C

Exit Question

We have just officially entered
the Fall season. What is your
favorite season and why?
Catalyst – October
1.
2.
3.
2
2 -1,
Monday Mystery
Element!
Element’s Greek name
means “moon”
Added to dandruff
shampoos
Protects against cancer
2011
Catalyst – October
1.
2.
3.
Monday Mystery
Element!
Element’s Greek
name means “moon”
Added to dandruff
shampoos
Protects against
cancer
2
2 -1,
2011
SELENIUM!
Today’s Agenda
Catalyst (New Groups after test)
 Gatorade/Powerade Test
 Unit 3 Test Review with Ms. Stroh
 Work Time
 Exit Question
HW: STUDYYYYYYY FOR THE TEST
TOMORROW!!!!

Today’s Agenda
SWBAT get ready to
DOMINATE tomorrow’s Unit 3
Test!

Unit 3– What You Need to Know…

Ionic, Covalent, Metallic Similarities and Differences
 Characteristics



Octet Rule
Lewis Dot Structures for Ions and Compounds
Ionic Formulas and Names
 Kriss-Kross,

No Prefixes, Transition Metals, Polyatomic Ions
Covalent Formulas and Names
 No

of Ionic and Covalent
Kriss-Krossing, Formula Subscripts = Name Prefixes
Determining Bond Type with Electronegativity
Difference
Get to Know Your Compounds
Partner up with someone in your group
 Ask each other, “If you were a chemical
compound, would you want to be ionic or
covalent and why?”
 Be ready to share each other’s answer

Octet Rule

While bonding, atoms will give, take,
and/or share electrons in order to
have a full valence (outer) shell (2 or
8 electrons)
Lewis Dot Structures

Draw the LDS for the following atoms and ions…


Model the ionic bond formation for…


Mg, S, Br, Al, O2-, K1+ , C4+
Lithium chloride
Draw the LDS for the covalent compounds…

SiF4, H2S, CO, SO
REVIEW OF
NAMING &
FORMULAS!
Yo Yo! Let’s break it down!
IONIC
COVALENT
Metal + Nonmetal
Nonmetal + Nonmetal
Writing Formulas:
Writing Formulas:
Kriss Kross charges Prefixes = subscript #s
Naming:
Naming:
2nd element ends in – 2nd element ends in –ide,
ide, ignore subscripts don’t ignore subscripts
– use prefixes
How do we know if our compound is
ionic or covalent?

Is it between a metal and a non-metal?
YES!!!

Then, it is ionic!!!
Is it between a non-metal and a nonmetal?
Then,
it is covalent!
Ionic Bond

Metal Cation: Li
Li

Nonmetal Anion: O
O
Ionic Bond

Metal Cation: Li
1+
Li

Nonmetal Anion: O
2O
Ionic Bond

Metal Cation: Li Nonmetal Anion: O
1+
Li
2O
Ionic Bond

Metal Cation: Li Nonmetal Anion:
O
Li2O
MgO
MgO
Magnesium Oxide
NBr3
NBr3
Nitrogen tribromide
Write the names and formulas…
First! Decide if it’s ionic or covalent!
Write names
1.
2.
3.
4.
5.
6.
7.
Na2O
CO2
CaBr
Na2CO3
Mg3P2
K2 S
N2S3
Write formulas
1.
2.
3.
4.
5.
6.
7.
Carbon monoxide
Barium nitrate
Xenon difluoride
Carbon tetrachloride
Sodium carbonate
Lithium fluoride
Nitrogen trifluoride
How Polar Is It?

Determine the polarity of each bond in the
following compounds by calculating the
electronegativity difference for each:
CO
2. AlP
3. N2
1.
4. HF
5. CaO
6. H2
Polarity and Electronegativity

Polar Covalent electrons are pulled
more toward one of the
atoms

Nonpolar Covalent electrons are shared
equally between atoms
Low ∆EN!
Big ∆EN!
Big Dog – Little Dog
Medium Dog – Medium Dog
Polarity Ranges
Bonds are not always purely
ionic (I) or purely covalent
(NPC). They could be slightly
ionic (VPC) or slightly covalent
(MPC).
Electronegativity Chart
Bond Type Chart
Range
Bond Type
0.0 – 0.3
Nonpolar Covalent
0.4 – 0.9
0.9 – 1.69
Moderately Polar
Covalent
Very Polar Covalent
1.7 or greater
Ionic
Unit 3 Review Work Time

Your Options:
 Review
Sheet
 Extra Worksheets provided by Ms. Stroh
 Read book

Not Your Option
 Wasting
time and being unproductive
Exit Question
1.
2.
What grade are you shooting for on this test?
What do you plan to actually do
today/tonight in order to prepare for the
test?
(Some options: study on your own, study with a
friend, complete review sheet, read book, come
at lunch or after school for tutoring, etc.)