VocabularyVocabulary
Chemical BondChemical Bond
– attractive force between atoms or ions attractive force between atoms or ions that binds them together as a unitthat binds them together as a unit
– bonds form in order to…bonds form in order to… increase stabilityincrease stability
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Chemical BondingChemical Bonding
atoms give up or gain electrons and are attracted
Na loses an e–
Na Na1+ + e–
(Metal)
Cl gains an e–
Cl + e– Cl1–
(Non-Metal)
ionic compounds = salts Na1+ + Cl1– NaCl
K1+ + NO31– KNO3
where NO31– is a polyatomic ion: a charged group of atoms
that stay together
Ionic BondingIonic Bonding
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n = 2
Na[Ne]3s1
n = 3
n = 3
+
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Cl[Ne]3s23p5
Na+
[Ne]Cl-
[Ne]3s23p6
NaCl
Transfer of electrons to achieve a stable octet (8 electrons in valence shell).
Properties of Ionic CompoundsProperties of Ionic Compounds
VERY HARD each ion is bonded to several oppositely-charged ions
HIGH MELTING POINTS many bonds must be broken
BRITTLE with sufficient force, like atoms are brought next to each other and repel
Writing Chemical Writing Chemical FormulasFormulas
The Swap n Drop MethodThe Swap n Drop Method
The Swap n Drop method is an easy way to The Swap n Drop method is an easy way to determine the formula of any ionic compound.determine the formula of any ionic compound.
The ionic compound can be the simple (binary) The ionic compound can be the simple (binary) ionic compound with just two elements, or one ionic compound with just two elements, or one that has a polyatomic ion as part of it.that has a polyatomic ion as part of it.
You can get the oxidation values directly off of You can get the oxidation values directly off of the the periodic tableperiodic table for most elements or they are for most elements or they are part of the part of the “Polyatomic Cheat Sheet”.“Polyatomic Cheat Sheet”.
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Calcium and NitrogenCalcium and Nitrogen
1.1. Ca NCa N
2.2. CaCa2+2+ N N3-3-
3. Ca3N2
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together. together.
Be BrBe Br
1.1. Be BrBe Br
2.2. BeBe2+2+ Br Br1-1-
3. BeBr2
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together. together.
Lithium OxideLithium Oxide::
1.1. Li OLi O
2.2. LiLi1+1+ O O2-2-
3. Li2O
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Magnesium NitrideMagnesium Nitride::
1.1. Mg NMg N
2.2. MgMg2+2+ N N3-3-
3. Mg3N2
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Lithium ChlorideLithium Chloride::
1.1. Li ClLi Cl
2.2. LiLi1+1+ Cl Cl1-1-
3. LiCl
Formulas With Transition Formulas With Transition MetalsMetals
The Swap n Drop method is also used when The Swap n Drop method is also used when dealing with metals that have more than one dealing with metals that have more than one oxidation number. (Copper, Iron, Lead, or Tin)oxidation number. (Copper, Iron, Lead, or Tin)
The oxidation number for these metals can be The oxidation number for these metals can be found in the name of the compound that contains found in the name of the compound that contains them.them.
Examples:Examples:– Iron (II) oxide – the Iron (Fe) used here has an oxidation Iron (II) oxide – the Iron (Fe) used here has an oxidation
number of 2number of 2– Lead (IV) sulfide – the Lead (Pb) used here has a Lead (IV) sulfide – the Lead (Pb) used here has a
oxidation number of 4.oxidation number of 4.
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Iron (III) OxideIron (III) Oxide::
1.1. Fe OFe O
2.2. FeFe3+3+ O O2-2-
3. Fe2O3
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Lead (II) ChlorideLead (II) Chloride::
1.1. Pb ClPb Cl
2.2. PbPb2+2+ Cl Cl1-1-
3. PbCl2
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Copper (I) Phosphide:Copper (I) Phosphide:
1.1. Cu PCu P
2.2. CuCu1+1+ P P3-3-
3. Cu3P
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Tin (II) Sulfide:Tin (II) Sulfide:
1.1. Sn SSn S
2.2. SnSn2+2+ S S2-2-
3. Sn2S2
4. SnS
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. ReduceReduce – if – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Lead(IV) OxideLead(IV) Oxide::
1.1. Pb OPb O
2.2. PbPb4+4+ O O2-2-
3. Pb2O4
4. PbO2
Polyatomic IonsPolyatomic Ions
Polyatomic ions Polyatomic ions are clusters of atoms are clusters of atoms that stay together as one unit and that stay together as one unit and carry an overall charge. Most carry an overall charge. Most polyatomic ions are negatively polyatomic ions are negatively charged.charged.
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Polyatomic Ionic Polyatomic Ionic CompoundsCompounds
ParenthesisParenthesis You need more than one polyatomic ion in your formula…This You need more than one polyatomic ion in your formula…This
means that you will have to use brackets. Use parenthesis means that you will have to use brackets. Use parenthesis whenever you need more than one polyatomic ion in the formula.whenever you need more than one polyatomic ion in the formula.
Example: Iron (III) nitrate…Example: Iron (III) nitrate…– Start with symbols and combining capacities…Start with symbols and combining capacities…
FeFe3 3 NONO3311
– After the Swap n Drop, you may get one of two possibilities…
FeNO33 OR Fe (NO3)3
The second option is right because it says you need two nitrate The second option is right because it says you need two nitrate clusters to go with every iron atom. The first option, which did clusters to go with every iron atom. The first option, which did not use reads as one iron atom and thirty-three oxygen atoms.not use reads as one iron atom and thirty-three oxygen atoms.
Fe(NOFe(NO33))3 3 is the correct formula! Use the parenthesis!is the correct formula! Use the parenthesis!
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Sodium NitrateSodium Nitrate::
1.1. Na NONa NO33
2.2. NaNa1+1+ (NO (NO33))1-1-
3. Na(NO3)
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Calcium ChlorateCalcium Chlorate
1.1. Ca ClOCa ClO33
2.2. CaCa2+2+ (ClO (ClO33))1-1-
3. Ca(ClO3)2
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Lithium PhosphateLithium Phosphate::
1.1. Li POLi PO44
2.2. LiLi1+1+ (PO (PO44))3-3-
3. Li3(PO4)
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Aluminum SulfateAluminum Sulfate::
1.1. Al SOAl SO44
2.2. AlAl3+3+ (SO (SO44))2-2-
3. Al2(SO4)3
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. ReduceReduce – if – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Tin (IV) CarbonateTin (IV) Carbonate::
1.1. Sn COSn CO33
2.2. SnSn4+4+ (CO (CO33))2-2-
3. Sn2(CO3)4
4. Sn(CO3)2
Reduce!
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. Reduce – if Reduce – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Ammonium PhosphateAmmonium Phosphate::
1.1. NHNH44 PO PO44
2. ( NH NH44)1+ 1+ ( PO PO44)3-3-
3. (NH4)3 ( PO4)
Swap it and Drop itSwap it and Drop it
StepsSteps (in order) (in order)
1.1. Write the chemical Write the chemical symbols.symbols.
2.2. Write the oxidation Write the oxidation numbernumber over the over the symbols.symbols.
3.3. Swap it and Drop it.Swap it and Drop it.
4.4. ReduceReduce – if – if necessary- the same necessary- the same numbers or a 2 & 4 numbers or a 2 & 4 together.together.
Magnesium CarbonateMagnesium Carbonate::
1.1. Mg COMg CO33
2.2. MgMg2+2+ (CO (CO33))2-2-
3. Mg2(CO3)2
4. Mg(CO3)
Reduce!