Vocabulary Chemical Bond –a–a–a–attractive force between atoms or ions that binds them together as a unit –b–b–b–bonds form in order to… iiiincrease

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






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






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







Magnesium NitrideMagnesium Nitride::

1.1. Mg NMg N

2.2. MgMg2+2+ N N3-3-

3. Mg3N2







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.







Iron (III) OxideIron (III) Oxide::

1.1. Fe OFe O

2.2. FeFe3+3+ O O2-2-

3. Fe2O3







Lead (II) ChlorideLead (II) Chloride::

1.1. Pb ClPb Cl

2.2. PbPb2+2+ Cl Cl1-1-

3. PbCl2







Copper (I) Phosphide:Copper (I) Phosphide:

1.1. Cu PCu P

2.2. CuCu1+1+ P P3-3-

3. Cu3P







Tin (II) Sulfide:Tin (II) Sulfide:

1.1. Sn SSn S

2.2. SnSn2+2+ S S2-2-

3. Sn2S2

4. SnS






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!







Sodium NitrateSodium Nitrate::

1.1. Na NONa NO33

2.2. NaNa1+1+ (NO (NO33))1-1-

3. Na(NO3)







Calcium ChlorateCalcium Chlorate

1.1. Ca ClOCa ClO33

2.2. CaCa2+2+ (ClO (ClO33))1-1-

3. Ca(ClO3)2







Lithium PhosphateLithium Phosphate::

1.1. Li POLi PO44

2.2. LiLi1+1+ (PO (PO44))3-3-

3. Li3(PO4)







Aluminum SulfateAluminum Sulfate::

1.1. Al SOAl SO44

2.2. AlAl3+3+ (SO (SO44))2-2-

3. Al2(SO4)3







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!







Ammonium PhosphateAmmonium Phosphate::

1.1. NHNH44 PO PO44

2. ( NH NH44)1+ 1+ ( PO PO44)3-3-

3. (NH4)3 ( PO4)







Magnesium CarbonateMagnesium Carbonate::

1.1. Mg COMg CO33

2.2. MgMg2+2+ (CO (CO33))2-2-

3. Mg2(CO3)2

4. Mg(CO3)

Reduce!

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Vocabulary Chemical Bond –a–a–a–attractive force between atoms or ions that binds them together as a unit –b–b–b–bonds form in order to… iiiincrease