Transcript Bonding_F2016

1
Adventures
of Oxygen
Clip
2
GOALS
1. Compare & contrast ionic and covalent bonds in
terms of electron position.
2. Predict formulas for stable binary ionic
compounds based on balance of charges.
3. Determine the Types of ions formed by
representative elements
4. Use IUPAC nomenclature for transition between
chemical names and chemical formulas of
- binary ionic compounds
- binary covalent compounds
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16
(IUPAC) International Union of Pure and Applied Chemistry
3 Why do Atoms Form Compounds?
• Stability.
• What makes an atom stable?
• Full outer energy level.
– Eight.
• They can either……
– 1) Gain electrons
– 2) Lose electrons
– 3) Share electrons
4
• A Chemical Bond holds
atoms together in a
compound.
• Two basic types:
1. Ionic
2. Covalent
5
Ionic Bonding
Remember: Atoms need a full outer energy
level to be stable. EIGHT!
6
Ionic Bonding
Opposites ATTRACT!
7
When Atoms gain or lose electrons,
they are called Ions.
3P
3P
3P
Anion
3P
3P
Cation
3P
• Metals
lose
electrons
to become
stable.
• Nonmetals
gain
electrons
to become
stable.
8
9
Atoms can gain or lose electrons
Ionization: requires energy
Why do atoms lose and gain
electrons?
To become more stable.
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Animation
Examples
Opposites Attract!
12
Properties of Ionic Compounds
• Crystalline solids at room temperature.
• Arranged in repeating threedimensional patterns
• Have high melting points
• Can conduct electricity
when melted or dissolved
in water
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14
Covalent Bonding
15
16
Hydrogen and Fluorine
Hydrogen and Chlorine
17
Single, Double, Triple
2 e-
4e-
6e-
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Clip
19
Unequal Sharing
Called Polar
δ+
δ_
Polar molecules
happen when
one atom has
a greater
positive charge
20
Properties of Covalent Molecules
• Many are gases
or liquids at room
temperature
• Composed of two
nonmetals.
• Have low melting
and boiling
points… covalent
bonds are weaker
than ionic bonds
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Covalent or Ionic?
(write the formula, then write “C” or “I”)
1. CO2
2. NaCl
3. H2O
4. MgCl2
5. NO2
6. Li2S
7. NaF
8. BeCl2
clip
9. BeO
10.HCl
11.KCl
12.H2O2
13.N2
14.Cl2
15.AgCl2
• Ionic and Covalent Bonding Review Clip
Goals
revisited
22
•Writing chemical formulas is a shorthand way
of indicating what a substance is made of.
•These formulas also let you know how many
atoms of each type are found in a molecule.
The chemical formula for water is H2O.
Carbon Dioxide is CO2.
Why does oxygen combine in different ratios,
in different compounds?
The chemical formula for table salt is NaCl.
Calcium Chloride is CaCl2.
Why does chlorine combine in different
ratios, in different compounds?
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The simplest compounds
are ones with only two
elements
These are called binary
KI, CO, H2O, NaCl
+1
+4
-4
Oxidation numbers
+2
+3
0
-3 -2 -1
Tell you how many
electrons an atom
must gain, lose or
share to become
stable.
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Oxidation numbers
+1
-1
Cl
We can predict the ratio
of atoms in ionic
valence
compounds based on 1electron
K
their oxidation numbers
All compounds
are
neutral
Tells you how many
electrons an atom
must gain, lose or
share to become
stable.
KCl
7 valence
electron
+1
-1
Br
Na
NaBr
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+2
Ca
-1
Br
To make it
ZERO, you need
CaBr
1 Ca & 22Br.
Subscripts show the number of atoms of
that kind in the compound
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1.
2.
3.
4.
5.
6.
7.
Now You Try writing Binary
Ionic formulas
K + Br
8. Ga + Br
Mg + Cl
Ca + I
K+O
K+I
Sr + Br
Na + O
Some elements have more than one
oxidation number (Chart p588)
+3
-2
+2
-2
Co
O
Co
O
Co2O3
CoO
We call these elements- Multivalent Elements
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Multivalent Practice
+2
Fe + O
1.
+3
2. Fe + S
+2
3. Cu + F
+3
4. Cr + Br
Naming Binary Compounds and
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Molecules
• Steps:
Example:
• NaCl
– If it is Binary1. Decide if it is an ionic or covalent
bond.
– Metal- nonmetal…..
» Ionic
– Nonmetal- nonmetal….
» Covalent
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If ionic …….
2. Check to see if any
elements are
multivalent.
3. If all single valent,
write the name of
the positive ion
first.
4. Write the root of
the negative ion and
add –ide.
Example:
• NaCl
Examples:
• CaO
• K2S
With a friend:
1. NaCl
2.K2O
3.AlCl3
4.BaF2
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If ionic …….
5. Check to see if any
elements are multivalent.
6. If multivalent ions,
determine the oxidation
number of the element.
7. Use Roman numerals in
parentheses after the
name of the element.
8. Write the root of the
negative ion and add –ide.
NiCl
Mn2S
Ionic-multivalent
Examples:
1.FeO
2.Fe2O3
3.CuO
4.Cu2O
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If Covalent...
2. Use Greek prefix to
Greek Prefixes
indicate how many atoms
1- monoof each element are in
2- dithe molecule
3- tri3. Add -ide to the more
4- tetraelectronegative element
5pentaExample:
6- hexa•PCl3
7- hepta•Phosphorous trichloride
•NO
8- octa•Nitrogen Monoxide
36 ¾
1.
2.
3.
4.
5.
6.
7.
8.
Naming Covalent Practice
P4S5
SF6
N2O5
H2O
NF3
SiO2
P2Br4
SO3
•
•
•
•
•
•
•
•
Tetraphosphorus Pentasulfide
Sulfur Hexafluoride
Greek Prefixes
1- monoDinitrogen Pentaoxide
2- diDihydrogen Monoxide
3- triNitrogen Trifluoride
4- tetraSilicon Dioxide
5- penta6- hexaDiphosphorus Tetrabromide
7- heptaSulfur Trioxide
8- octa-
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Name the following:
Mixed Practice
1. KBr
1. Potassium
Bromide
2. HCl
2. Hydrogen
Monochloride
3. MgO
4. CaCl2
5. H2O
6. NO2
3. Magnesium
Oxide
4. Calcium
Chloride
5. Dihydrogen
Monoxide
6. Nitrogen
Dioxide
7. CaS
8. Cr2O3
9. FeO
10. LiBr
7. Calcium
Sulfide
8. Chromium
(III) Oxide
9. Iron (II)
Oxide
10.Lithium
Bromide
End of
Chemical
Bonding
Study Packet
38
Goals
revisited
GOALS
1. Apply the Law of Conservation of Matter
by balancing following types of chemical
equations:
•Synthesis
•Decomposition
• Single Replacement
•Double Replacement
2. Demonstrate the Law of Conservation of
Matter in a chemical reaction
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Chemical Reactions
• A chemical reaction is a change in which
one or more substances are converted into
new substances.
– Rearrangement of bonds in compounds and
molecules.
• Chemical Equations make it possible to see
clearly what is happening during a chemical
reaction
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Chemical equations are a
shorthand way to show
chemical reactions.
Reactants
Products
H2 + O2
H2O
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Conservation of Mass
42
H2 + O 2
H2O
Does this meet the
Conservation
of 2Mass
2 Hydrogen
2 Oxygen
Hydrogen atoms & one
atoms
atoms
Oxygen atom
Law?
Must Balance the Equation to
show Conservation of Mass.
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Can add coefficients to Balance equations.
2 H2 + O 2
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Steps:
2 H2O
2
42
21
Balanced!!
1. Count Atoms on both sides
2. If not Balanced, add coefficients to balance.
3. Recount atoms after adding each coefficient.
4. Keep adding coefficients until balanced.
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Chemical Reactions
• You start with one or more
compounds and turn it into
different compounds.
Vapors of hydrogen
chloride in a beaker and
ammonia in a test tube
meet to form a cloud of
a new substance,
ammonium chloride.
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1.Synthesis
2.Decomposition
3.Single Replacement (Single
Displacement)
4.Double Replacement
(Double Displacement)
Synthesis
“to make”
A + B
AB
2Cu + O2
2CuO
2H + O2
2H O
2
2
Animation
Decomposition
“to breakdown”
AB
2H O
A + B
2
2H + O
NaOH
Na + OH
2
2
Single Replacement
When one element replaces another element
in a compound
A + BC
Cu+AgNO3
AC + B
Cu(NO3)2+ 2Ag
The more reactive metal will always
replace the less reactive metal. (p749)
Single Replacement
• Clip
Double Replacement
Positive Ion of One compound replaces the
positive ion of another compound and a
Precipitate is formed.
AB + CD
Ba(NO3)2+KSO4
AD + CB
2KNO3 + BaSO4
Review Clip
Clip
Animation
Review Clip
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Chemical Reactions and Energy
• All chemical reactions release or absorb
energy.
– Heat, light, sound
• Chemical reactions are the making and
breaking or bonds.
1. Exergonic
• Chemical
reactions that
releases energy
are called
exergonic.
– Glow sticks
• If heat is
released, it is
called
exothermic.
2. Endergonic
• Chemical reactions that require energy
are called endergonic.
• Ex: Cold Packs
• If heat is absorbed, it is called
endothermic
Catalysts and Inhibitors
Some reactions proceed slowly.
• They can be sped up by a catalysts.
– Catalysts are not used up in the
reaction.
– EX: enzymes (biological catalysts)
Some reactions proceed too fast.
• They can be slowed down by
inhibitors.
– EX: Preservatives in food
GOALS Revisited…..
1. Compare & contrast ionic and covalent bonds in terms of
electron position.
2. Predict formulas for stable binary ionic compounds based
on balance of charges.
3. Use IUPAC nomenclature for transition between chemical
names and chemical formulas of
• binary ionic compounds
• binary covalent compounds
4. Apply the Law of Conservation of Matter by balancing the
following types of chemical equations:
• Synthesis
• Decomposition
• Single Replacement
• Double Replacement