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Chemical Bonding. 1. 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. 4. Apply the Law of Conservation of Matter by balancing the following types of - PowerPoint PPT Presentation
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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
GOALGOALSS
2
3416
Why do Atoms Form Compounds?
•Stability.•What makes an atom stable?
•Full outer energy level.•Eight.•Chart page 576.
3
•A Chemical Bond holds atoms together in a compound.
•Two basic typesTwo basic types:
•Ionic•Covalent
4
Ionic Bonding
Transfer of
electrons
from one
atom to
another
atom.
Occurs between
metals and nonmetals.
Remember: Atoms need a full outer energy level to be
stable.
EIGHT!
5
Occurs between metals and nonmetals.
Metals are electron donors.
Non-metals are electron accepters.
Called compounds.
6
Covalent Bonding
The
sharing of
electrons
between
atoms.
Occurs between nonmetal
s and nonmetal
s.Called
Molecules.
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1.CO2
2.H2O
3.NaCl4.MgCl2
5.NO2
6.H2SO4
7.NaF
9.NaPO4
10.HCl11.NaF12.KCl13.CaCO3
14.N2
15.Cl2
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•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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+1
+2
-1-2
-3+3
+4 -4 0Oxidation numbers
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Tell you how many electrons an atom must gain, lose or share to become
stable.
We can predict the ratio of atoms in ionic compounds based on
their oxidation numbers
Oxidation numbers
K Cl+1
-1
KClTells you how many electrons an atom must gain, lose or share to become
stable.
1 valence electron
7 valence electronAll All
compounds compounds are neutralare neutralThat means the That means the
overall charge is overall charge is
ZERO!ZERO!
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Subscripts show the number of atoms of that kind in the compound
Na
Br
+1
-1
NaBr
Ca Br
+2
-1
CaBr2
To make it ZERO, you
need 1 Ca & 2 Br.
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Some elements have more than one oxidation number (Chart p588)
Fe O
+3
-2
Fe2O
3
Fe O
+2
-2
FeOWe call these elements- Multivalent
Elements22
Now You Try writing Binary Ionic formulas
1.K + Br2.Mg + Cl3.Ca + I4.K + O5.K + I6.Sr + Br7.Na + O
8.Ga + Br9.Fe+2 + O10.Fe+3 + O11.Cu+2 + F12.Cr+3 + O13.Mg + O14.Al + P
Cations: ammonium, NH4+
Anions: nitrate, NO3-
sulfate, SO42-
hydroxide, OH-
phosphate, PO43-
carbonate, CO32-
chlorate, ClO3-
permanganate, MnO4-
chromate, CrO42-
Polyatomic Ions
Groups of Covalently Bonded
atoms that stay
together.
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Try these…….1.Na + SO4
2.Mg + PO4
3.Ca + CO3
4.Na + OH5.Mg + OH6.NH4 + OH
7.K + PO4
8.NH4 + NO3
9.H + SO4
10.Ca + SO4
11.K + NO3
12. Na + PO4
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Naming Binary Compounds and Molecules
• Steps:– If it is Binary-1. Decide if it is an ionic or covalent
bond.– Metal- nonmetal…..
» Ionic– Nonmetal- nonmetal….
» Covalent
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Example:• NaCl
If ionic …….
2.2. Check to see if Check to see if any elements are any elements are multivalent.multivalent.
3.3. If all single If all single valentvalent, write the , write the name of the name of the positive ion first.positive ion first.
4.4. Write the root of Write the root of the negative ion the negative ion and add –ide.and add –ide.
Examples:1.NaCl2.K2O
3.AlCl34.BaF2
5.KI6.Li2O
If ionic …….2. Check to see if any
elements are multivalent.
3. If multivalent ions, determine the oxidation number of the element.
4. Use Roman numerals in parentheses after the name of the element.
5. Write the root of the negative ion and add –ide.
Examples:
1.FeO2.Fe2O3
3.CuO4.Cu2O
5.PbCl4
6.PbI2
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If Covalent...2. Use Greek prefix to
indicate how many atoms of each element are in the molecule
3. Add -ide to the more electronegative element
Greek Prefixes1- mono-2- di-3- tri-4- tetra-5- penta-6- hexa-7- hepta-8- octa-
Example:•NO
•Nitrogen Monoxide•PCl3
•Phosphorous trichloride
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If it contains a polyatomic ion...2. Write the name
of the positive ion.
3. Write the name of the polyatomic ion.
Examples:1. NaCO3
2. KNO3
3. NaC2H3O2
Example:•KOH
•Potassium Hydroxide•CaCO3
•Calcium Carbonate
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Name the following:
1.KBr2.HCl3.MgO4.CaCl5.H2O
6.NO2
7.CuSO4
8.CaSO4
9.NH4OH
10.CaCO3
11.Cu(ClO3) 2
12.Cr2O 3
13.SrI 2
14.CCl4
33
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 happen during a chemical reaction
35
Chemical equations are a shorthand way to show
chemical reactions.
Reactants Products
H2 + O2 H2O
36
H2 + O2 H2O
2 Hydrogen atoms
2 Oxygen atoms
2 Hydrogen atoms & one Oxygen atom
Does this meet the Conservation of Mass
Law?
Must Balance the Equation to show Conservation of
Mass.
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2
H2 + O2 H2O2
4 1 2 2
2
4
Balanced!!
Can add coefficients to Balance equations.
Steps:
1. Count Atoms on both sides2. If not Balanced, add coefficients to
balance.3. Recount atoms after adding each coefficient.
2
4. Keep adding coefficients until balanced.
39
1.Synthesis2.Decomposition
3.Single Replacement (Single Displacement)
4.Double Replacement (Double Displacement)
41
Single ReplacementWhen one element replaces another
element in a compound
A + BC AC + BCu+AgNO3 Cu(NO3)2+
2Ag
The more reactive metal will always replace the less reactive
metal. (p749)
Double ReplacementPositive Ion of One compound replaces the positive ion of another compound
and a Precipitate is formed.
AB + CD AD + CBBa(NO3)2+K2SO4 BaSO4 2KNO3
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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.
51
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 InhibitorsSome 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
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
GOALS GOALS Revisited…..Revisited…..