Unit 11

COVALENTBONDING

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Period: TEST: March 9th

Unit 12 - Covalent Bonding - Calendar

February 26thNotes #1: BondTypes andProperties

lwk: Page 4

29th

Hwk: Page 7

HWK: REVIEW Page14- 16

Tth

VSPER Lab

wk: Page 9

8th

Review Covalent

Bonding

2th

lotes #4: Bondolarity (pg 10)

Hwk: Page 11

th

CovalentBondingTest

3th

Notes #5: MoleculePolarity, andIntermolecular

Forces

Hwk: Page 13

lOth

DLA

March 1

Notes #3:Electrical andMolecular GeometryCPg 8)

Notes #2: CovalentBonding and LewisStructures

(pg 5-7)

4th

Covalent

BondingActivity

1 lth

DLA

Spring Break

Notes #1: Bond Types and Properties

ionic Compounds and Properties (4 rain)https:fwww, youtube.comiwatch ?v=T AVwvCÿUewLk&list=PLflÿTuBca SOr8aVsoÿKEOWU&index=lList the properties of Ionic Compounds:!..ÿc.t,ÿ& c.ÿ"iÿeM'ÿ ,::t,ÿ £ÿcÿ +.eÿ,ÿ7,"M'l..,.-,r,ÿ-...

2. I-t ,0. 'ÿ

3. 6 .-.,ÿ-,aÿ

8 rÿdOn 5Draw Example:

'c_)Q©ÿ@ 'ÿ

Draw Example:

Metallic Bonding and the Properties of Metal (3.5 rain)https:/iwww.youmbe.comiwatciÿ?v::OamgxMAmPÿ &irÿde×=S&list=PLtÿuBca SOrgaVsqv27nÿ,)D7U V0aBKEOWUList the properties of Ionic Compounds:The electrons in a metallic compound are able to ÿove throughout the entire compound, The electronscan be described as a ÿ.o. ('ÿ ÿ.. ÿ./tb.;. ÿ-r,:,,'iÿ

,_:>: O,JÿAitÿ 3 ÿ.10cot t-7ÿg

@(g ,

Molecular/Covalent Compounds and Properties (4 rain)s:i/www.voutubeocom/watch?v:::ÿXtEzÿ,A&Jndex=4&lÿst=PLt%uBca S0rtÿaVsÿÿ

©7UV0aBKVOWUList the properties of ionic Compounds:

t!

i;t:-',ZS or rÿ::n

k.o--ÿ* cÿ,- e,/ex....¢,,,,de y4. 0 0 nC,ÿ (:o,q(JiaL.qÿ

2. ÿ':'-"tty 0(,,,:4 ,:.,,

i cÿ.,, i'ae i H,ÿ

Draw Example:

! e.:.+,,.:', s

Notes #1: HOMEWORK: Three types of bonds - metallic, ionic and covalent.

each have their own characteristics.

Metallic bonds are formed by pooledvalence electrons of metallic atomsproviding the negative charges to holdpositively charged metallic ions together.This bonding structure provides forrelatively high melting points and easyreshaping (bending, flattening). Thedelocalized electrons provide high electricalconductivity.

Ionic bonds are formed when metallicatoms donate valence electrons to non-

metallic atoms. The resulting ions haveopposite charges and attract each other intorigid lattices. This bonding structure giveshigh bond strength that provides brittlesubstances with high melting points and lowconductivity. If the lattice is disrupted bybeing heated or dissolved in water, the ionsbreak apart and find movement easier.Conductivity of molten or aqueous ions ismuch higher than that of solids.

Covalent bonds are formed when two non-metallic atoms approach and share valenceelectrons. These are the strongest of allbonds. Covalent networks form when atomsbond each to several others, making aninterlocking web of atoms. Covalentnetworks are very hard to disrupt, givingthese substances very high melting pointsand low conductivity in any state. Moleculesform when a few covalent bonds formbetween a countable number of molecules,as in CO2 or H20. While the bonds withinthe molecule are very strong, the moleculesare so small that we commonly deal with avery large number of them. One moleculerequires little energy to separate fromanother, so these substances have very lowmelting points, often below roomtemperature. Most liquids and gases that weare familiar with are molecular. Becausemolecules hold their electrons so tightly,molecules also tend to be poor conductors.

Classify the following as characteristics ofa compound that contains metallic (M),ionic (I) or covalent (C) bonding.

__ÿ 1. Contains a metal and a nonmetal ion

(and possibly polyatomic ions)/ÿf\ 2. Contains 'sea' of delocalized electrons• _. 3. The smallest particle is the formula unit

4. The smallest particle is the molecule5. Particles are held together by strongelectrostatic forces=

! 6. Particles are held together by relatively/ÿ weak intermolecular forces

__ 7. The elements in the compound share

valence electrons

8. The elements in the compound gain andlose valence electronsi 9. Are usually soluble in water

T 10. Are electrolytes when dissolved in wateror molten (liquid) and conduct electricity

11. Have low melting and boiling points__ 12. Have high melting and boiling points

(2 answers)" 13. Often exist as gases or vaporize easily at

room temperature

14. Are hard crystalline solids at roomtemperature

15. Malleable and able to be flattened16. Are rigid and brittle17. An example is MgCI2

____ÿ__ÿ 18. An example is CCk

19. Conduct electricity in solid state20. Its structure looks like this:Qÿ

f

>-- 21. Its structure looks like this:

/ÿ,, 22. Its structure looks like this:

Notes #2: Lewis Structures of ionic compounds

Ionic Bonding -Generally occurs between ÿ ÿ cÿ( ÿ ÿAÿ,ÿ rÿcÿ'ÿ- rÿ>,!§

Can also occur with oÿ,,lÿ/ÿmÿ ioaÿInvolves •ÿ -eÿ.ÿa& ÿr electrons, followed by electrostatic attraction.

Covalent Bonding -Generally occurs between ÿt, n - ÿ ÿ;.ÿo-ÿ1 ÿ'

Involves ÿIÿ\,ÿ of electrons, rather than transfer.J

Octet Rule - Atoms will acquire, through sharing or transfer, the electron configuration of alÿÿ ÿ ÿ ÿ lÿ " This happens in order for the atoms to ainstability.• Mostÿnoblegaseshave ÿ valenceelectrons. ,"ÿ> )-gÿ +ÿ ÿl ÿJÿ

O 'ÿ. 01 is the exception. ,,. ÿ'W-ÿ--ÿ-m -ÿ

• These elements do not need a full octet: tq ÿ, H ÿ'ÿ A! e-ÿ.,ÿ ÿ, \ÿ/ ÿ'

Valence Electrons - The electrons in the highest occupied energy level. There are two ways to

determine the number of valence electrons.A. Using the electron configuration: lsÿ2sÿ2pÿ3s(ÿlÿ how many valence electrons are in this

element? ÿ .ÿ ÿ- Liÿ

B. Look at the group number to determine valence

electrons.

Dot Models - The number of dots is equal to the numberof Vÿo,ÿ iÿm ,ÿ, electrons.

Example: Phosphorus " ÿo(Oo

'ÿ Valence Electrons in Each•

Examples of Ionic compounds: NaCI MgBrz

' - °,"

N,.,. i,. ,, 2 " '-'

Lewis Structures for Molecules -

Each atom in the molecule is connected by bonds.Covalent bonds are shared paired of electrons, and they are represented with a

Pairs that are not shared are called

A single bond is created by GÿA double bond is created by '.ÿ

A triple bond is created by ;?

shared pair of electrons. *Draw it: !ÿ -i-i

shared pairs of electrons. *Draw it: g"- C

shared pairs of electrons. *Draw it: N ÿAÿu'ÿ

m

.

Steps for Drawing Lewis Structures:Determine the Lewis Dot Structures of all of the elements in theFormula.

Example: (]H4

////

/ Practice:

Lewis StructureStructure

HzO

- %, , t !

oÿ ,1

HCP ?

i

2. Draw a skeleton of the molecule, connecting atoms in the molecule

with rÿ. ¢, ÿ'ÿ.ÿ (l sharedpair).• Usually the ÿ atom in the molecular formula is

r J

• jq ÿ} Arÿ.ÿ.ÿ is never central -

• Nature likes symmetry.

• Hydrogen always only gets i i) cÿ',ÿÿ of electrons.• Each atom should have

r'ÿcÿt ÿ:.,i c ÿ ÿ ÿ/ÿ 1ÿ7, ÿ ÿ" c. ! ,ÿc,i,,.ÿ ÿ unless it is an

to the octet rule.

/.ÿ ÿ to fulfill theoctet rule, you will need a fiaultiple bond.

17";

Lewis

..................................................................................................................... ................................... i

C02 ÿ.. :, :.,, .... ÿ'ÿ

Remember: Exceptions to the octet rule:

• Atoms with less than an octet. (B, AI, H, Be)

Nz

t,D(1)by3tÿ

Notes # 2: Homework

Complete the tables belowCompound Lewis D/ÿ .yo f

eiements

( f ÿ,o .ÿ ÿÿ

' hiCCI4 /ÿ.ÿ

,0

ur

r/

p_,

Lewis DotStructure

Drawing

.L

HCI

H

H

fÿ

j ÷

Compound

02

BeFz

HCN

CHÿCI

Lewis Dot ofelements

(;

J

Lewis DotStructure

Drawing

f4

fl '

@,--_ .ÿ'J --(ÿ,j.

Notes #3: Electron and Molecular Geometry

Electron Geometry:• The geometry based on the number of electron groups on the central atom.

o It does not matter if the groups are a single bond, a multiple bond, or lone pairs.

o Know the following Geometries:Electron Geometry:

Number of atomsbonded to theCentral Atom:

Linear

i--

Trigonal Planar Tetrahedral

,i

Picture:

- ÿlI

Molecular Shape (Geometry):• In order to predict the specific molecular shape, we assume the valence electrons

:.-i'ÿl! each other. The molecule adopts whichever 3D geometry U.ÿ Iÿ [°'iÿX

o, ÿ, r,-ÿ,,ÿ,ÿ.ÿ.:ÿ this repulsion. ,

• Some of the names for the Molecular Geometry are the same as the Electron Geometry

Know the following Molecular Geometries:

Molecular

Geometry

Number OfAtoms BondedTo The CentralAtomNumber Of LonePairs On TheCentral AtomBond Angle

Picture

Linear

f

f

, ÿ).

! ..

Trigonal TetrahedralPlanar

i'

,o.,' 'X

/ÿ ., Xx

o d , ÿ.!"

Pyramidal

tl ÿ- "

Bent

.-.,

!",._ .,,:'i )

I

./

'( Ii tj.- ÿ,

Notes #3 HomeworkGeometry and VSPER shapes

1. Explain the VSEPR theory in your own words: Iÿ i ÿ

2. Use the picture to the right to answer the next 3 questions: *ÿ ÿiÿ .. i ÿ !*ÿ' " "

H,;O ,Ha. How many electron groups are in the molecule? .i ÿ ' ' ÿ-- " ÿ" "l ÿ" ' ÿ ÿ" ÿ

b. What electron geometry will the molecule have? ÿ: ÿ 1c. What molecule geometry will the molecule have?

Complete the table below

FormulaLewis Structure

Number ofatoms

C2H4

AIBr3

HF

Electron

i

Sketchbonded to

the CentralAtom:

j,

/

Geometry

!,

I

# lone pairs ofelectrons

around central

atom

J

MoleculeGeometry

7&. i ," (ÿ

[

r

!

7

Notes #4: BOND Polarity

In ÿ:. t, ÿ/ bonds, shared pairs of electrons are pulled between the nuclei of atoms sharing

them. ÿ Sometimes electrons are pulled equally and sometimes they are not. This has to do withelectronegativity. *Recall: ele ctroÿe gativiÿ is theÿ 1 p ÿ ÿ I ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ" ÿ Iÿ 4 ÿ ÿ eÿectroÿs •

1. Nonpolar covalent bonds: When electrons are shared " ÿ,...', ÿ,,,,,

a. The molecule will be electrically neutral - little to nb difference in electronegativity

2. Polar covalent bonds: The electrons are Shared' :",ÿ' :ÿ, , tÿ :/ due to electronegativitya. The more electronegative atom will have a "I}ÿ., ,:-ÿ;,, ÿ-o,ÿ attraction for the bonded

electrons and will have a slightly ,' ,. ,, ,-.ÿ'- Charge.

b. The less electronegative atom will havea slightly ÿ,. ÿ.ÿ ÿ ÿ .... charge.

c. Ex: HCI - Look up the electronegativities on the chart.H: "ÿ, i ,Cl: (:

o There are two ways to show polarity: HC1 has a polar bond

+ ÿ " The lowercase Greek ÿ The arrow points to the

H 1 CI ÿeÿerde.lÿashowsghatÿhe H moreelÿctronegaÿiveaÿoms ]nvotved acquire or -- atom.

only partial charges.

Ex: Water

Y

4A ÿA gÿ 7A

] 'ÿ ÿ,ÿ; : "1 ÿ'ÿ

The difference inelectronegativitiesindicates the typebond the atoms will

form.

Electronegativity Type of Bond ExampleDifference

0.0--0.3 ÿ I

0.4-1.0

1.o-z.o , 1 1'i

>2.0 : ÿ, ,

Question: What typeof bond will form

between:

• N and H?

F and F?

l

• Ca and O?

Notes #4: Homework

1-3 True/False1) In a polar covalent bond, the more electronegative atom has a slightly positive charge.

T ÿl

2) In general, non-metallic elements have greater electronegativities than metallic elements.

3) If the electronegativity difference between two atoms is greater than 2, they will form an ionicbond.

4) What is the difference between a polar and a non-polar bond? (answer in terms of electrons)

5) If an element with an electronegativity of 0.3 bonds with an element with an electronegativity of :.- ÿ: 2.9. What type of bond is between these elements?

6) State whether the following contain polar, non-polar or ionic bonds.a) KF'ÿ:,,ÿ -> :ÿ-: ÿ e) NazO -;:> :ÿ ÿ> -" --

b) SOz ÿ . "> )ÿ. ÿ,. _. -: ".- .... :

7) Draw the Lewis structure for the following compounds. Label any polar bonds. Identify theirmolecular geometry. (shape)

%:

Jÿ

a) HzS ÿÿ ,ÿ--i-t-- d) CHCI3

J"! ,.

b) CSz 'G :' '

c)

, ) ,ÿ

1

HBr

,o

e) OFÿ

_ l

d) CF4

i

(j i "-"- -

£ •

1:

Notes #5: MOLECULE Polarity and I.termolecular ForcesMolecule Polarity:If a molecule has all nonpolar bonds then the molecule is l ÿ Tÿ ÿ ÿ ÿ ÿ Iÿ ÿ ÿ

If a molecule has a polar bond then the whole molecule is usually ÿ" ÿ,To determine if a molecule is polar or nonpolar, look at the central atoml

, but not always.

has ÿ lone pairs and has L. ÿ ÿ ." " / 51ÿ •of atoms attached to it,

haSL:, lone pairs but ÿ ;ÿ :,: -- atoms attached to it, the molecule is,

has lone pairs, the molecule is , alÿ ÿA. ÿ .

the molecular geometry is L ,,

' !

1. If the central atomthen the molecule is

2. If the central atom3. If the central atom

*In other words: Ifthe molecule is ¢

.... ÿ ÿ lÿ ÿ. , the bond polarities cancel, and

Example: carbon dioxide

.r

Example: methane

jl

' j.,ÿ

Example: water

oÿ

€

In a polar molecule, one end has ahas poles is called a .ÿ .... ÿ(

Dipole interaction - occurs when !,,, ,,

l' Iÿ ' ;,., are attracted to one another

Hydrogen bonding - occurs when a ,", 'ÿ, ,•ÿ.

atom involved in an

attracted to an adjacent molecule. This is the:.! ,, vÿ ÿ intermolecular force.

Extremely polar bonds: ' ÿ

Dispersion Forces- occurs between". b ÿ ÿ "ÿ ÿ ÿ Iÿ ÿ molecules,

a "" ' iÿ ÿ "1" " t ÿ / 11 charges

ositive charge and the other has a negative charge. A molecule that

' ÿ ÿ' ', - ' ...... neighboring particles

Eleetmstatiÿ

Heliÿra atoÿn I I-ÿlittra atÿrcL 2 8- ÿ- ÿ- ÿ"(a) ®)

HH \0

\ /,,0 --- H--Cÿ ..... H

dipoleinteraction

Recall: Intermolecular Forces are the

HydrogenBonding

/ chemical bondH /

N H

1/ Oÿ-H

H ................. /H ,q

O-

Notes #5 Homework

1) Label the following structures. Also include the bond angles for each structure.

r'

a)t

Which of the above structures would be polar molecule(s) no matter what elements werebonded in it? 1ÿ t ' < .ÿ iiÿ,. ,ÿ,,,ÿ

2) State whether the following contain polar, non-polar or ionic bonds.a) NaF :.." ..... d) Br2 :',.ÿr'

b) SeOz ,:<, ";' e) LizO '/,,

c) POz !iÿ'.ÿ f) N2 l ÿ ÿ1ÿ

i

i,

r ,II

a) HOOH b) CO2 c) H20 d) BF3

4) What are the attractive forces between adjacent water molecules called?

/ ,

Il¸

,. i>

3) Draw the structural formula for the following compounds. Label any polar bonds anddetermine whether the molecule itself is polar or non-polar.

ii'

5) In your own words, explain how or why a molecule can have polar bonds, but the molecule isnonpolar.

i ii £?, I'¢ÿ:ÿ-/I('-

6) Draw the Lewisstructures for CFÿ and CHÿCIÿ and then explain which molecule is the more.... - ,t.i-ÿ-,.- fi :oA 7-, 'ÿ

polar, i,, ,' ' ÿ:-

I-f 1,i I:'" I,. ' i

I/' I

, /fI' i ' ÿo., /

/" I //

:, ',t

Ji' .ÿ ÿ ÿ "ÿ .

l !,

. - i'rl

D.O

Study Guide-Covalent Bonding

if.DiRECTIONSÿ Use the word banks in the pvreÿ to aÿvcer ÿ questfopÿs about ionlÿ covalent & meÿlÿ bonds.

Vaÿnce eLÿectyons are .........shared, mobifeo ÿranÿ#erÿect)

Eleÿ'lÿS inVOlW-ÿri' tmeÿal, nonmetal +nonmetalÿ nonmeta!l + mebÿil)

Paÿ prelÿkq ÿat)oÿs & electron&atomk caLionÿ + anio,ÿ)

ofalJÿaCÿor!? ['eleÿtroÿtÿfdc al:ÿ:raÿtÿon.aLt(ÿ.]eÿion between mÿattiÿ particles.shared e between atoms)

Melÿg & bOtlÿ Pcÿnt? fhiÿh, lowI

Water solubÿ? thig, h° fOWll

Condÿ a ÿ tgood, pÿ

Conducÿy when melted or aqueous?tgood, pooÿl

Malleable? tyes, no)

Hard, brittle, er soft? ta bored ÿype cnn havemore than one ÿtÿwerÿl

is tlÿ type of bond feurÿ tn compounÿtye& nol

I

yl

i , IL

,,'1 t

f

,iÿL '

i ,

I

<.. , ....

II ,

I.

.

For each of the following elements, determine the number of valence electrons and draw the Lewis DotDiagram (Electron Dot Structure) for that element.

A. sodium , C. oxygen

B. helium .... D. neon

L Lt

Describe each type of bond. For each type, provide at least one example.

A. nonpolar covalent bond, ÿ ÿ ,ÿ , , - ,ÿ , ' ,. '*. ÿ : 'ÿ , . "ÿ:ÿ

B. polar covalent bond

3. Complete the table below ..... ""

C. ionic bond

Type of BondSingleDoubleTriple

Number of Electrons Number of Electron Pairs

. What is electronegativity?'l

(

0

5. Determine if the following bonds are ionic, polar, or nonpolar using the electronegativity values in the table

below.

.

A. H-H D. Na-F

IJ ÿ ÿ ÿ ÿ ÿ ÿ ÿF ÿlÿ ÿ ÿ ÿ ÿ ÿ ÿ

B. N-H i

C-OC.

E. N-Br! L

F. C-Fÿ ÿ

For the polar bonds in #5, which bond was the most polar?

Element ElectronegativityH 2.1

Br 2.8

C 2.5

N 3.OO 3.5

F 4.0

CI 3.0I 2.5

Na 0.9

P 2.1

. For the POLAR bonds (andonly thepolar) bonds in #5, assign the positive pole(ÿ+) and negative pole(8+) for

the bonÿ._' ÿ 1 ÿ ÿ ÿlÿ ÿ lÿ ÿ 1 ÿ rÿ ÿ F ÿbÿ ÿ ÿ ÿ

J ÿ ÿ Ll I

. What shape occurs if there were three atoms and one lone pair of electrons?

9. What electron geometry does BCI3 have? iÿ i ÿ ÿ ÿ

10. Draw the shape of water. The two sets bf lone pairs o:f electrons cause the atoms to repel and create what shapeP

[--ÿlI / iÿf

If the lone pairs of electrons were bonded to atoms, what would this shape then be called? ÿ:" i ÿ ". : , i ÿ , : ii

11. Which two molecular shapes are polar no matter what elements are involved? Explain why.

12. In the Lewis structure for-CO4ÿ how many-unpaired electrons would appear on the structure?

13. According to VSEPR theory, why do molecules adjust their shapes?/

il

h. " " 1'ÿ ÿ ' .ÿ " ' i¸ oÿ

¢0O_

Covalent Bonding Content Frame

A.

Compound

H2

N2

E°

F.

G.

H.

I.

D.

C. H2S

COz

NCI3

NH3

PCI3

CHCG

HCN

B.

.ewis Dot ofElements

l#) # ...... % l J

l Iiÿ l

o

Lewis Structure of

Compound (Drawing)

t '

ti '" iI

y'l

llÿ

i ,

, 5t

Polar or Non-PolarBonds?

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "NP")

(Label each bondwith a "P" or "ALP")

Polar or Non-PolarMolecule?

,:'\ÿ I

i'

Ir-