Download 4 CovalentBonds new - Mr-Durands

Good Day! July 5, 2017
• Starter: Please write the formula for the following
compounds (you will need your Table of
polyatomic ions)
• Boron Sulfate
Calcium Phosphate
• Ammonium Oxide
Barium Acetate
• After the starter we will do a little more practice.
• Then move on to Covalent bonding
• Tomorrow we will have a quiz on Naming bonds.
Starter Answers
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Boron Sulfate
B+3
SO4-2
Calcium Phosphate
Ca+2
PO4-3
Ammonium Oxide
NH4+1
O-2
Barium Acetate
Ba+2 C2H3O2-
• B2(SO4)3
• Ca3(PO4)2
• (NH4)2O
• Ba(C2H3O2)2
More practice only this time the other
way around.
Please write the name for the following compounds
(you will need your Table of polyatomic ions)
• CaCl2
• K3 N
• Na2CO3
• Al2(SO4)3
Answers
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CaCl2
K3 N
Na2CO3
Al2(SO4)3
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Calcium Chloride
Potassium Nitride
Sodium Carbonate
Aluminum Sulfate
More
• CuSO4
– Cu2SO4
• Pb(CO3)2
– PbCO3
• CrPO4
– Cr3(PO4)2
• Copper (II) Sulfate
– Copper (I) Sulfate
• Lead (IV) Carbonate
– Lead (II) Carbonate
• Chromium (III) Phosphate
– Chromium (II) Phosphate
Good Afternoon! July 5, 2017
• Starter: What are the covalent bonds?
• Today we will be working on Covalent bonding
• Then we will have a quiz on Naming bonds.
There is a Dangerous Menace
• Dihydrogen Monoxide? Thousands of people
die every year from inhalation of this deadly
compound, and today we will discuss it.
Dihydrogen Monoxide
• DHMO Link
The deadly molecule Dihydrogen Monoxide.
• The prefix Di means 2, and the prefix
mono means 1.
• So Dihydrogen Monoxide is H2O
– I didn’t lie to you, many people do die from
too much Dihydrogen Monoxide, they
drown.
– True statement: this was a urban legend that
went around as an e-mail that went around a
few years ago and a city in Washington State
banned the substance before they realized it
was water!
Why the confusion?
• Well it turns out that Water is a Molecule
that bonds covalently. That means it doesn’t
transfer electrons like the compounds we
studied before. Water bonds by SHARING
electrons. This means that we have to have a
totally different way to name these
compounds.
Molecular Compounds
• Molecular compounds are held held
together by covalent bonds, so what do you
think is another name for these compounds?
• Covalent Compounds
• They share electrons for the same reason
that Ionic compounds transfer electrons,
They are trying to become stable.
How can you tell the difference
between Ionic and Molecular?
• Ionic have a metal in them. The only
exception that we will be working with is
NH4+ because it is a positive polyatomic and
it takes the place of the metal.
The bond between two atoms that share
electrons is __________.
A covalent bond
Why do you need to use prefixes with
molecules?
Lithium Sulfide = Li2S
They don’t have charges and there can be
many different combinations.
Sharing Electrons
• Some atoms of nonmetals are unlikely to
lose or gain electrons.
• Remember when we talked about the
elements in Group 4?
• They don’t like to make ions.
Sharing Electrons
• They would have to either gain or lose
four electrons in order to have a stable
outer level.
• Since losing electrons takes so much
energy they are willing to Share rather
than try and take electrons away from
each other.
• Video
Single Covalent Bonds
• A single covalent bond is made up of two
shared electrons.
• A water molecule contains two single
bonds. In each bond, a hydrogen atom
contributes one electron to the bond and
the oxygen atom contributes the other.
• The result of this type of bonding is a
stable outer energy level for each atom in
the molecule.
Sharing Electrons
• The attraction that
forms between atoms
when they share
electrons is known as
a covalent bond.
• The molecule is held
together because the
nuclei (positive
because of the
protons) are attracted
to the electrons that
are between them.
• Link to video
Multiple Bonds
• A covalent bond also can contain more than
one pair of electrons.
• An example of this is the bond in nitrogen
(N2).
Multiple Bonds
• A nitrogen atom has five electrons in its
outer energy level and needs to gain three
electrons to become stable.
• It does this by sharing its three electrons
with another nitrogen atom.
Multiple Bonds
• When each atom contributes three
electrons to the bond, the bond
contains six electrons, or three pairs
of electrons.
• Each pair of electrons represents a
bond.
• Therefore, three pairs of electrons
represent three bonds, or a triple bond.
Naming Binary Covalent
Compounds
• Covalent compounds are those formed
between elements that are nonmetals.
• Some pairs of nonmetals can form
more than one compound with each
other.
• In the system you have learned so far,
each of these compounds would be
called nitrogen oxide. You would not
know from that name what the
composition of the compound is.
Using Prefixes
• Scientists use Greek
prefixes to indicate how
many atoms of each
element are in a binary
covalent compound.
• Notice that the last vowel
of the prefix is dropped
when the second element
begins with a vowel as in
pentoxide.
Rules for Naming Molecular/Covalent
Compounds
First word in the compound:
Give the prefix designating
the number of atoms of the
first element present. We
don’t use the prefix mono
when there is only one
atom of the first element.
CO2: No prefix for C (only one)
N2O3:
di
Name the first element.
CO2:
carbon
N2O3:
dinitrogen
Rules for Naming Molecular/Covalent
Compounds
• Second word in the compound:
• Give the prefix designating the number of
atoms of the second element present.
• CO2:
carbon di
• N2O3: dinitrogen tri
• Name the root of the second element.
• CO2:
carbon diox
• N2O3: dinitrogen triox
• Add –ide to the root of the second element.
• CO2: carbon dioxide (official name)
• N2O3: dinitrogen trioxide (official name)
Rules for Writing Formulas for
Molecular/Covalent Compounds
• First symbol in the formula:
• Write the symbol of the first element.
• Sulfur Dichloride:
S
• Dicarbon tetrabromide: C
• Look for a prefix for the first element if it’s
there, use the table to find the right subscript.
• Sulfur Dichloride:
S (no prefix)
• Dicarbon tetrabromide: C2 (di = 2)
Rules for Writing Formulas for
Molecular/Covalent Compounds
• Second symbol in the formula:
• Write the symbol of the second element.
• Sulfur Dichloride:
SCl
• Dicarbon tetrabromide: C2Br
• Look for a prefix for the second element if
it’s there, use the table to find the right
subscript.
• Sulfur Dichloride:
SCl2
(di = 2)
• Dicarbon tetrabromide: C2Br4 (tetra= 4)
Answers
• N2O4
• PCl5
• NO
• CCl4
• SCl2
• Dinitrogen Tetroxide
• Phosphorus Pentachloride
• nitrogen monoxide
– or nitrogen oxide
• Carbon Tetrachloride
• Sulfur Dichloride
Answers
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Sulfur Hexafluoride
Pentanitrogen Heptoxide
Diodine tetrachloride
Triastatine Octoxide
Phosphorous Mononitride
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SF6
N5 O 7
I2Cl4
At3O8
PN
Now the Quiz
• http://highered.mcgrawhill.com/sites/0078600510/student_view0/
unit5/chapter20/math_practice.html