Phy Sci Unit 5
Bonding and Compounds
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Iowa Core Curriculum
Phy Sci Unit 5
Bonding and Compounds
Understand and apply knowledge of the structure and properties of matter.
•
Chemical bonds
Atoms interact with one another by transferring or sharing electrons that are the furthest from the nucleus.
These outer electrons govern the chemical properties of the element.
•
•
Molecular and ionic structures
Physical properties of chemical compounds
Bonds between atoms are created when electrons are paired up by being transferred or shared. A substance
composed of a single kind of atom is called an element. The atoms may be bonded together into molecules or
crystalline solids. A compound is formed when two or more kinds of atoms bind together chemically.
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Phy Sci Unit 5
Bonding and Compounds
Chapter 5 Section 1 (p. 150-156)
EMC Unit 5
Notes
What is the number of electrons that all atoms would like to have?
What are the two types of compounds?
What happens to their electrons?
What happens to their electrons?
Ionic Bonds
Covalent Bonds
Ionic Bonds are between what types of elements?
Bonds
Covalent Bonds are between what types of
compounds?
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L_________
energy
O_ ________
to fil l the ir
of
El ectrons
El ectrons
B___ _______
S___ ____________ __
atoms
T___ ____________ ____
Ionic
Bonds
Covalent
forms
forms
M_________
have high
have low
are bad
are bond s between
M__________
are bond s between
are good
C___ _______
P___ _______
N___ _______
C
_______ _
and
N___ _______
and
B ________
P ________
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E___ _______
for exampl e:
M__________
N__________
for exampl e:
of
E___ _______
Phy Sci Unit 5
Bonding and Compounds
of
C___ ______
and
5
Bond Identification
1. When atoms share electrons to fill their outermost energy levels, they form
________________________ bonds.
2. When atoms transfer electrons to fill their outermost energy levels, they form
________________________ bonds.
3. Indicate whether the atoms listed below will share electrons or transfer electrons (HINT: when
electrons are transferred, both atoms will have complete outermost energy levels. Otherwise, atoms
share electrons.)
a.
O -- O
a. ____________________
b.
K -- Cl
b. ____________________
c.
C -- O
c. ____________________
d.
H -- F
d. ____________________
e.
I -- I
e. ____________________
f.
S -- O -- O
f. _____________________
g.
Na -- Na -- S
g. ____________________
h.
Li -- Cl
h. ____________________
i.
Ca -- Br -- Br
i. ____________________
j.
N -- N
j. ____________________
4. Write IONIC or COVALENT under each substance below to identify the type of bond.
a. Calcium chloride
b. Sulfur trioxide
c. Phosphorus pentaflouride
d. Sodium iodide
e. Carbon monoxide
f. Cesium fluoride
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Draw the bonding between sodium and chlorine.
What charges do the elements end up with?
Sodium
Chlorine
What is the rule for Ionic Bonding?
Where are they written?
Superscripts
What do we use them for?
Subscripts
Where are they written?
What do we use them for?
Where are they written?
What do we use them for?
Where are they written?
Coefficients
Parentheses
What do we use them for?
Examples?
Examples?
Examples?
Examples?
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Sample Problems:
MgCl2
# of Magnesiums:
# of Chlorines:
3MgCl2
# of Magnesiums:
# of Chlorines:
Mg3N2
# of Magnesiums:
# of Nitrogens:
4Mg3N2
# of Magnesiums:
# of Nitrogens:
(NH4)2O
# of Nitrogens:
# of Hydrogens:
# of Oxygens:
3(NH4)2O
# of Nitrogens:
# of Hydrogens:
# of Oxygens:
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What are the rules for naming an ionic compound?
•
•
NaCl
Sample Problems:
Name the following compounds
ZnO
LiBr
Mg3N2
BaS
K3P
Combining metals and nonmetals
What is the charge on a calcium ion?
What is the charge on a nitride ion?
Calcium nitride
Draw the bonding between calcium and nitrogen.
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Steps for writing ionic formulas
1. ____________________________________________________________________
2. ____________________________________________________________________
3. ____________________________________________________________________
Sample Problems:
Beryllium iodide
Potassium sulfide
Magnesium oxide
Strontium fluoride
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ChemQuest 19
Name: ____________________________
Date: _______________
Hour: _____
Information: Naming Ions
To write an ion, you write the symbol of the atom and put the charge in the upper right corner.
Consider the following examples: Al3+, O2-, Mg2+. You should verify that each of the charges is
correct.
Positive and negative ions are named differently. Positive ions retain the same name as the
parent atom. For example, Al3+ is called the “aluminum ion” and Mg2+ is called the “magnesium ion.”
Negative ions are named a little differently. For negative ions, you change the ending of the name to
“-ide”. Therefore, O2- is named oxide and P3- is named phosphide.
Critical Thinking Questions
1. Write the symbol (including the charge) and name for each of the ions for each of the following:
a) Ca
b) Cl
c) N
d) K
e) S
f) B
g) P
Information: Ionic Bonding and Formulas
There are two ways in which atoms can “bond” to each other and form a compound. The means of
bonding that we will consider now is called ionic bonding, which occurs between a metal and a
nonmetal. As you know, opposite charges attract. Ionic bonding is when two ions of opposite charge
attract and bond to each other forming an ionic compound. Consider the following examples of
formulas for ionic compounds:
•
•
•
•
One Na+ (sodium ion) and one Cl- (chloride ion) bond to make NaCl, “sodium chloride.”
One Mg2+ (magnesium ion) and two F- (fluoride ion) bond to make MgF2, “magnesium fluoride.”
Three Ca2+ (calcium ion) and two N3- (nitride ion) bond to make Ca3N2, “calcium nitride.”
One Al3+ (aluminum ion) and one N3- (nitride ion) bond to make AlN, “aluminum nitride.”
The small numbers at the bottom right of each symbol in a formula are called “subscripts”. Subscripts
tell us how many of each type of atom are present. For example in the formula Mg3N2 there are three
magnesium ions and two nitride ions.
Critical Thinking Questions
2. Consider the formula NaCl in the above example. It tells us that one Na+ ion is bonded to one Clion. What is the overall charge for NaCl? Is it positive, negative, or neutral?
3. Consider MgF2. This formula tells us that one Mg2+ ion bonds with two F- ions. What is the overall
charge on MgF2?
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4. What is the overall charge on any ionic compound?
5. Why is calcium nitride written like Ca3N2 and not something like CaN2 or Ca2N3? In other words
why do exactly three calcium ions bond with exactly two nitride ions?
6. The formula Ca3N2 can never be written as N2Ca3. To find out why, take note of each of the four
example formulas given above.
a) In terms of charge, what do the first ions named all have in common?
b) In terms of charge, what do the second ions named all have in common?
c) Now, why can’t Ca3N2 ever be written like N2Ca3?
7. There are two rules to follow when writing formulas for ionic compounds. One has to do with
charges (see questions 4 and 5) and the other has to do with which atom to write first and which
one to write second (see question 6). What are these two rules?
8. What is wrong with the following formulas?
a) Al2S
b) PNa3
c) Mg2S2
9. Write the formula and name for the compound that forms when the following atoms form ionic
compounds. The first is done for you.
a) nitrogen and sodium
b) barium and sulfur
c) magnesium and iodine
Na3N
sodium nitride
d) oxygen and aluminum
e) calcium and phosphorus
f) sodium and sulfur
10. Given the following compounds, determine the charge on the unknown ion “X”.
a) X2S
b) MgX
c) X3P2
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Chemical Formulas Pairs Check
Directions: Write the chemical formula for each word formula listed. Check your partner as they are
completing their formula. Praise or coach each other until both partners understand all twenty
formulas.
1. Sodium Chloride
2. Magnesium Oxide
______________________________
_______________________________
3. Aluminum Sulfide
4. Potassium Oxide
______________________________
_______________________________
5. Calcium Chloride
6. Lithium Nitride
______________________________
_______________________________
7. Lead (II) Oxide
8. Iron (III) Flouride
______________________________
_______________________________
9. Copper (I) Flouride
10. Zinc Oxide
______________________________
_______________________________
11. Rubidium Bromide
12. Potassium Chloride
______________________________
_______________________________
12. Titanium (III) Sulfide
13. Calcium Iodide
______________________________
_______________________________
14. Lithium Phosphide
15. Silver Oxide
______________________________
_______________________________
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Formula Writing for Binary Ionic Compounds
Write the formula for the following binary compounds.
1. sodium bromide
___________________________________________
2. Magnesium oxide
___________________________________________
3. Strontium sulfide
___________________________________________
4. barium nitride
___________________________________________
5. silver chloride
___________________________________________
6. Francium oxide
___________________________________________
7. Lithium bromide ___________________________________________
8. magnesium phosphide ___________________________________________
9. aluminum iodide
___________________________________________
10. calcium oxide
___________________________________________
11. strontium arsenide
___________________________________________
12. Beryllium chloride
___________________________________________
13. Strontium selenide
___________________________________________
14. Barium phosphide
___________________________________________
15. magnesium chloride
___________________________________________
16. Radium oxide ___________________________________________
17. barium iodide
18. Calcium bromide
19. Lithium bromide
___________________________________________
___________________________________________
___________________________________________
20. Cesium sulfide ___________________________________________
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Nomenclature Writing for Binary Ionic Compounds
Write the name for the following binary ionic compounds.
1. CaBr2
___________________________________________
2. AlCl3
___________________________________________
3. Zn3N2
___________________________________________
4. KCl
___________________________________________
5. Na2S
___________________________________________
6. AlN
___________________________________________
7. CsI
___________________________________________
8. Ca3P2
___________________________________________
9. BaO
___________________________________________
10. BeF2
___________________________________________
11. FeCl2
___________________________________________
12. FeCl3
___________________________________________
13. Ag2O
___________________________________________
14. CuS
___________________________________________
15. CoP
___________________________________________
16. MnBr3
___________________________________________
17. NiN
___________________________________________
18. ZnF2
___________________________________________
19. BiP2
___________________________________________
20. VO2
___________________________________________
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Inside Plug-in Car Tech's Race to Production
Big automakers and promising startups say electric vehicles are coming as soon as next year, but
there's a lot of work to be done—by scientists—before lithium-ion batteries are ready for mainstream
hybrids.
By Chuck Tannert
Published on: February 6, 2008
Popular Mechanics Magazine
The future of American motoring will be—at least in part—battery-powered. Now, from unveilings at last
month’s Detroit auto show to updates from plug-in startups and entries for the Automotive X Prize, it’s
becoming increasingly clear that the lithium-ion pack is what will get us there. Almost every top-tier carmaker
has announced plans to use the technology, but they haven’t exactly said when we might see roadworthy li-ionpowered vehicles. The consensus is that they’ll probably start to appear in the 2010 to 2012 time frame—though
no one’s promising anything.
Even though lithium-ion already runs everything from laptops to screwdrivers, the reality remains that only a
handful of smaller companies actually make these electric cars for production (or soon will). And whether it’s
AC Propulsion (a converted Scion xB), Aptera (a sleek three-wheeler), HST (a plug-in Shelby Cobra), Hybrid
Technologies (an all-electric Mini Cooper) or even Tesla (a high-performance sports car), none of these startups
put out large quantities, and the vehicles they do make are pricey. It all comes down to that battery.
So what’s up with the final push before li-ion is finally ready for prime time? We checked in with the lab rats
from Detroit to Silicon Valley to find out when emissions-free driving will switch from dream to dealership.
Issue No. 1: Battery Chemistry
Sounds simple, right? Pick a chemical makeup and run with it. Not so fast. “There are as many, if not
more, recipes for these batteries as there are companies that supply them,” says Denise Gray, director of hybrid
energy storage systems for General Motors. “Automakers need to experiment to find which works best for
them. That takes time. We need them to perform as a function of driving style, location and climate. They need
to deliver both power and range when needed, every time it’s needed.”
Like other batteries, those that use lithium work by shuttling ions (electrically charged atoms or groups
of atoms) between their electrodes. When they’re charging, the ions travel in one direction. When they’re
discharging, they go in the other. The most widely used have a positive electrode made from cobalt or
manganese oxide and a negative electrode made from graphite. The electrolyte (the material through which the
ions pass from one electrode to the other) is a lithium-based gel or polymer. These types of batteries are mainly
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used in laptops, and are not well-suited for the automotive environment, where they’re subject to rapid
discharging and recharging, much higher power demands and extremes of heat and cold. The problem is that the
chemistry isn’t stable enough, so batteries suffer from overheating—and that can have an explosive effect.
The most promising electrode chemical makeups, then, involve nano-engineered materials like phosphates of
iron, lithium-titanate spinel and, most recently, bundles of silicon nanowires. Making an electrode out of these
tiny particles increases the available surface area for the ions to bond to and exchange electrons, avoiding a
bottleneck that used to result in deformation (and diminished effectiveness) of traditional materials like
graphite. The smoother-flowing electrode decreases the battery’s internal resistance and improves its ability to
store and deliver energy.
Some battery companies have battery recipes that are ready for series production now, at least for mild
hybrids. Milwaukee-based Johnson Controls/Saft, one of the industry’s top manufacturers for outsourcing
hybrid chemistry into Saturn’s Vue series and Mercedes’ diesel hybrid (details on next page), has been touting
research it calls NCA, which has been approved for mild and full conversions by OEM powerhouses. “It has
demonstrated the required combination of power, range, safety and longevity,” says Mike Andrew, director of
Government Affairs and External Communications at Johnson.
Meanwhile, Toyota appears to be close, if not locked into its chemistry, for a demo fleet of plug-in
hybrids. In Detroit earlier this month, Toyota’s president Katsuaki Watanabe said they would be accelerating
development to have a large-scale (an estimated several-hundred-to-a-thousand-vehicle) test fleet in service by
2010 or earlier. When pressed, he said these demo cars could be on the road by late 2009. So, in order to meet
that target, we hear Toyota has the chemistry nearly finalized for their first-generation of electric cars.
Even so, there doesn’t seem to be a clear winner here or a one-size-fits-all solution. “The chemical
makeup will, in part, depend on application,” says Dave Vieau, CEO of battery supplier A123 Systems. “One
type of lithium-ion might be better for use in hybrids, while another is better for plug-ins.” As PM detailed last
year in a cover story on plug-in research, A123 is one of the leaders in this field, with phosphate particles in its
electrodes that shrink to about a hundredth of the size of the oxide particles used in existing li-ion batteries. That
was good enough to score the MIT geeks at A123 a massive contract with GM to work on its Chevrolet Volt,
the power system for which they’re currently developing.
And it’s going to take a lot more practical application to figure what works over the long run. “It’ll take
companies like AC Propulsion and Tesla to put some products on the market to see what works and what
doesn’t,” says Tom Gage, president and CEO of AC Propulsion, makers of a Scion-based electric vehicle
conversion they call the eBox. “Right now, the market is too small for the top tiers to produce anything.”
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1.
What metal are they planning to use in car batteries?
2.
What kind of charge will this form?
3.
What else do they use these kinds of batteries for?
4.
What do the batteries need to deliver in order for companies to start producing them?
5.
In your own words, how do these batteries work?
6.
Draw a picture of the positive electrode (include what its made of and draw the formula) and the
negative electrode. Be sure and label which way the electrons are traveling.
7.
What does the word diminished mean in the paragraph?
8.
Why would people want to use electric cars? Be sure and include pros and cons for your argument.
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What is a Covalent Bond?
Draw the bonding between two chlorine atoms.
What are the rules for naming covalent bonds?
•
•
Name these covalent compounds.
ICl5
N2O
Sample Problems:
CO2
PCl5
CO
P3F6
Nitrogen dioxide
Sulfur hexafluoride
Dicarbon hexahydride
Nitrogen monoxide
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Name: ____________________________
Date: _______________
Hour: _____
Information: Terminology
Recall that an ionic bond results from the combination of a metal and a nonmetal. A covalent bond is
the type of bond between two nonmetals. Covalent bonds are formed by neutral atoms that share
electrons rather than by charged ions. When a compound is formed by sharing electrons, the
compound is called a molecule or molecular compound. It is important to note that ionic compounds
are not called molecules. The largest class of molecules are called organic molecules. Carbon is the
distinguishing mark of organic compounds.
Critical Thinking Questions
1. Circle any of the following compounds that would properly be called a “molecule”.
a) H2O
b) CO2
c) NaCl
d) Mg3P2
e) N2O5
Information: Naming Covalent Compounds
There are several prefixes used to name molecules. The name “carbon oxide” is not sufficient
because carbon and oxygen sometimes form CO2 and sometimes CO. Prefixes are necessary to
distinguish between them.
Formula
N2O4
SF6
XeCl5
SO3
CO
Name
dinitrogen tetraoxide
sulfur hexafluoride
xenon pentachloride
sulfur trioxide
carbon monoxide
Critical Thinking Questions
2. Fill in the table to indicate which prefix is used to represent the numbers. The first one is done for
you.
Prefix
Number
1
mono
2
3
4
5
6
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Covalent Naming Practice
1. Triphosphorus Pentachloride __________________________________
2. Sulfur Triflouride
_______________________________________
3. Silicon Tetrabromide _______________________________________
4. Dinitrogen Octabromide ______________________________________
5. Pentacarbon decahydride ______________________________________
6. Tricarbon hexahydride ________________________________________
7. Heptasilicon Monoiodide ______________________________________
8. Phosphorus dioxide
_________________________________________
9. Tetracarbon pentaflouride _______________________________________
10. Sulfur dihydride _______________________________________________
Covalent Formula Writing
1. C6H10 _____________________________________________________________
2. P3O7 ______________________________________________________________
3. NCl2 ______________________________________________________________
4. Si4H9 _____________________________________________________________
5. C2F5 ______________________________________________________________
6. S7H2 _____________________________________________________________________________________________
7. PBr8 _____________________________________________________________________________________________
8. N4Se5 ____________________________________________________________________________________________
9. C6H6 _____________________________________________________________________________________________
10.
P4Br9 _____________________________________________________________________________________________
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Breathalyzer reading
Directions: Use the reading below to answer the questions that follow.
There are many faults with the way a breath testing machine analyses the air that is introduced to it.
These tests can be very unreliable and susceptible to attack by a lawyer who understands the
weakness of a "Breathalyzer".
One of the major defects in many methods of blood-alcohol analysis is the failure to identify ethanol
(also referred to as ethyl alcohol) to the exclusion of all other chemical compounds. To use the
terminology of scientists, such methods are not specific for ethanol: They will detect other compounds
as well, identifying any of them as "ethanol." Thus a client with other compounds in his blood or
breath may have a high "blood-alcohol" reading with little or no ethanol in his body.
This problem of no specificity is most noticeable in the use of infrared breath analyzing instruments
(the most popular type of breath testing machines used today). Yet they are particularly susceptible
to giving false readings due to no specificity. The technical reason for this lack of specificity is that
most breath machines are not designed to detect the molecule of ethyl alcohol (ethanol), but rather
only a part of that molecule—the methyl group. In other words, it is the methyl group in the ethyl
alcohol compound that is absorbing the infrared light, resulting in the eventual blood-alcohol reading.
Thus the machine will "detect" any chemical compound and identify it as ethyl alcohol if it contains a
methyl group compound within its molecular structure. The "Breathalyzer" assumes that the methyl
group is a part of an ethyl alcohol compound.
Acetone and acetaldehyde, interestingly, can be found on the human breath. In fact, recent studies
have found that over one hundred chemical compounds can be found on the breath at any given
moment in time. More important, approximately 70 to 80 percent of these compounds contain methyl
groups. And the infrared breath machine will detect each of these as "ethyl alcohol".
1. What is one of the major faults of the “Breathalyzer” test?
__________________________________________________________________________________________
__________________________________________________________________________________________
2. Ethanol has another name. It is also referred to as
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
3. In the second paragraph, what does “no specificity” mean?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
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4. Why are the infrared testers not able to pick out only ethanol in someone’s breath?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
5. Acetaldehyde can be found in the human breath. Does this affect the “Breathalyzer” readings?
How?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________
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