Unit 4: Chemical Bonds

Vocabulary

1. Electron configuration

2. Electron dot diagram

3. Electron transfer

4. Valence electron

5. Ionic bond6. Cation7. Anion

8. Crystal lattice9. Molecule10.Covalent bond11.Polarity12.Binary

compound13.Chemical

formula14.Extrapolate15.Oxidation16.Polyatomic ion

**Cannot be printed directly from Quizlet

Purpose: Understand the meaning of a stable electron configuration &

represent atoms using electron dot diagrams.

• Purpose on top of ISN 90.• Notes/Practice on ISN 91. (Lewis

Structure Handout)• Homework on ISN 90:

– Write your own step-by-step rules for making an e- dot diagram.

– WKBK 93 Create

Lewis Structures (Electron Dot Diagrams)

1) Find your element on the periodic table.

2) Determine the number of valence electrons.

3) This is how many electrons you will draw.

Lewis Structures

• Find out which group (column) your element is in.

• This will tell you the number of valence electrons your element has.

• You will only draw the valence electrons.

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Groups - Review

•Each column is called a “group”

•Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.

Group 1 = 1 electron

Group 2 = 2 electrons

Group 8 = 8 electrons

Except for He, it has 2 electrons

•The electrons in the outer shell are called “valence electrons”

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3, 4, 5, 6, 7

Lewis Structures1) Write the

element symbol.2) Carbon is in the

4th group, so it has 4 valence electrons.

3) Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.

C

Lewis Structures

C

1) Check your work.

2) Using your periodic table, check that Carbon is in the 4th group.

3) You should have 4 total electrons, or dots, drawn in for Carbon.

Lewis Structures

C

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

H

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

P

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Ca

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Ar

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Cl

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

Al

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Purpose: Understand how atoms obtain a stable electron configuration by

transferring or sharing electrons & differentiate molecules based on the type

of bonds within.• Purpose on top of ISN 92.• Notes/Practice on ISN 93. Ionic or

Covalent Bond handout.• Homework on ISN 92:

– Write your own rule for determining whether an element grouping will have an ionic bond or a covalent bond.

– WKBK 123 Determine

H2O2 hydrogen atoms

1 oxygen atom

Chemical Formula• Shows:

1) elements in the compound2) ratio of their atoms

¨ Strong attractive force between atoms

or ions in a molecule or compound.

¨ Formed by:

• transferring e- (losing or gaining)

• sharing e-

¨ Octet Rule• most atoms form bonds in order to

have 8 valence e-

• full outer energy level• like the Noble Gases! Ne

¨ Stability is the driving force behind bond formation!

¨ Transferring e-

¨ Sharing e-

Comparison Chart

IONIC COVALENT

Electrons

MeltingPoint

Soluble in Water

Conduct Electricity

OtherProperties

transferred from metal to nonmetal

high

yes (solution or liquid)

yes

crystal lattice of ions, crystalline solids

shared between nonmetals

low

no

usually not

molecules, odorous liquids & gases

Purpose: Explore the transfer of electrons & characteristics of ionic

bonding & ionic structure.

• Purpose on top of ISN 94.• Notes/Practice on ISN 95.• Homework on ISN 94:

– WKBK 98 all – Write your own rules for remembering

the difference between cation and anion.

¨ Attraction between 2 oppositely charged ions• Ions - charged atoms• formed by

transferring e-

from a metal to a nonmetal

¨ Cation- positive charge because of lost electron(s)

¨ Anion- negatively charged ion because of gained electron(s)

• ions form a 3-D crystal lattice

NaCl

Purpose: Understand how electrons are shared by exploring the

formation of covalent bonds & the characteristics of covalent bonds &

molecules.• Purpose on top of

ISN 96• Notes/Practice on

ISN 97. Write Activity instructions here also.

• Homework on ISN 96: Write a short (2-3 sentence) summary of what you learned from the activity.

• Covalent Bonding video

Covalent Bonding Activity:1. Write the symbols for each

element. 2. Use beans to create the Lewis

structures for each. Each type of atom has a different color.

3. Rearrange the electrons (beans) to show the sharing of electrons.

4. Draw circles to show the sharing of electrons.

5. Draw the bond structure using symbols & lines. Use 1 line for each pair of electrons that is shared.

6. Write the chemical formula for each molecule.

7. Use a colored pencil to draw where the bean was when you remove it.

• Attraction between neutral atoms– formed by sharing e- between two nonmetals– Covalent Bonding Animation

• covalent bonds result in discrete molecules

Cl2 H2ONH3

Beans & Covalent Bonds Activity

These molecules will be done on ISN 80. Make sure you leave plenty of room between each molecule.

1. Hydrogen + Hydrogen

2. Hydrogen + Oxygen

3. Chlorine + Chlorine

4. Oxygen + Oxygen

5. Carbon + Oxygen

6. Carbon + Hydrogen

Purpose: Explore the nature of covalent bonds by examining the polarity & non-polarity of simple

covalent compounds.

• Purpose on top of ISN 98• Notes/Practice on ISN 99. Draw the

pictures of the types of bonds.• Homework on ISN 98: WKBK 109 all

& top of 110.

¨ Nonpolar Covalent Bond

• e- are shared equally

• usually identical atoms

¨ Polar Covalent Bond• e- are shared unequally between 2

different atoms

• results in partial opposite charges

+ -

¨ Nonpolar

¨ Polar

¨ Ionic

View Bonding Animations.

Purpose: Name simple binary covalent compounds by looking at

the chemical formula.Purpose: Name binary covalent

compounds & write their formula using prefixes.

• Purpose on top of ISN 100.• Notes/Practice on ISN 101.• Homework on ISN 100: WKBK p.

112 all & p. 113 Write

Naming Binary Compounds

Binary Compound?

Metal Present?

Does the metal formmore than one cation?

Type IIIUse Greek

Prefixes

Type IUse the elementname for the cation.

Type IIDetermine the charge of the cation; use a Romannumeral after the cationname.

Yes

Yes

YesNo

No

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 98

¨ Write the names of both elements.

¨ Change the final ending to -ide.

¨ Add prefixes to indicate subscripts.

¨ Only use mono- prefix with oxide.

A. Molecular Names

Prefixes – Binary Molecular CompoundsGreek Prefixes for Two Nonmetals

Number Indicated Prefixes

1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona-10 deca-

¨ CCl4

¨ N2O

¨ SF6

• carbon tetrachloride

• dinitrogen monoxide

• sulfur hexafluoride

A. Molecular Names

¨ Write the more metallic element first.

¨ Add subscripts according to prefixes.

B. Molecular Formulas

¨ phosphorus trichloride

¨ dinitrogen pentoxide

¨ dihydrogen monoxide

• PCl3

• N2O5

• H2O

B. Molecular Formulas

Binary Molecular Compounds

N2O dinitrogen monoxideN2O3 dinitrogen trioxideN2O5 dinitrogen pentoxide

ICl iodine monochlorideICl3 iodine trichloride

SO2 sulfur dioxideSO3 sulfur trioxide

¨ The Seven Diatomic Elements

Br2 I2 N2 Cl2 H2 O2 F2

B. Molecular Formulas

Binary CompoundsContaining Two Nonmetals (Type III Compounds)

1. ________________ diarsenic trisulfide

2. ________________ sulfur dioxide

3. P2O5 ____________________

4. ________________ carbon dioxide

5. N2O5 ____________________

6. H2O ____________________

As2S3

SO2

diphosphorus pentoxide

CO2

dinitrogen pentoxide

dihydrogen monoxide

Purpose: Name simple binary ionic compounds by looking at the chemical formula.Purpose: Extrapolate the chemical formula of binary ionic compounds from the names by using the oxidation states of the ions.

• Purpose on top of ISN 102.• Notes/Practice on ISN 103.• Homework on ISN 102:

– Worksheet

Naming Binary Compounds

Binary Compound?

Metal Present?

Does the metal formmore than one cation?

Type IIIUse Greek

Prefixes

Type IUse the elementname for the cation.

Type IIDetermine the charge of the cation; use a Romannumeral after the cationname.

Yes

Yes

YesNo

No

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 98

A. Oxidation Number• The charge on an ion.• Indicates the # of e- gained/lost

to become stable.1+

2+ 3+4+3- 2- 1-0

¨ Write the names of both elements, cation first.

¨ Change the anion’s ending to -ide.

B. Ionic Names

¨ NaBr

¨ CaO

¨ BaCl2

• sodium bromide

• Calcium oxide

• barium chloride

B. Ionic Names

¨ Write each ion. Put the cation first.¨ Overall charge must equal zero.

• If charges cancel, just write the symbols.• If not, crisscross the charges to find

subscripts.

C. Ionic Formulas

¨ potassium chloride

¨ magnesium nitride

¨ copper(II) chloride

• K+ Cl- KCl

• Mg2+ N-3 Mg3N2

• Cu2+ Cl- CuCl2

C. Ionic Formulas

¨ calcium oxide

¨ aluminum chloride

¨ iron(III) oxide

• Ca2+ O2- CaO

• Al3+ Cl-1 AlCl3

• Fe3+ O2- Fe2O3

C. Ionic Formulas

Purpose: Name the compound & write the formula for ionic

compounds containing polyatomic ions.

• Purpose on top of ISN 104.• Notes/Practice on ISN 105. Attach

list of common polyatomic ions & WKST 57 Chart on this page also.

• Homework on ISN 104:– WKST 58– WKBK 101-102 all

¨ Write the names of both elements, cation first.

¨ Change the anion’s ending to -ide.

¨ Write the names of polyatomic ions.

¨ For ions with variable oxidation #’s, write the ox. # in parentheses using Roman numerals. Overall charge = 0.

Ionic Names

¨ NaBr

¨ Na2CO3

¨ FeCl3

• sodium bromide

• sodium carbonate

• iron(III) chloride

Ionic Names

¨ Write each ion. Put the cation first.¨ Overall charge must equal zero.

• If charges cancel, just write the symbols.• If not, crisscross the charges to find

subscripts.¨ Use parentheses when more than one

polyatomic ion is needed.¨ Roman numerals indicate the oxidation #.

Ionic Formulas

¨ potassium chloride

¨ magnesium nitrate

¨ copper(II) chloride

• K+ Cl- KCl

• Mg2+ NO3- Mg(NO3)2

• Cu2+ Cl- CuCl2

Ionic Formulas

¨ calcium oxide

¨ aluminum chlorate

¨ iron(III) oxide

• Ca2+ O2- CaO

• Al3+ ClO3- Al(ClO3)3

• Fe3+ O2- Fe2O3

Ionic Formulas