Chap 1 Bonding

We knew, the word organ have close relationship with the word Organism

Have you ever come across the word organ/organism …….?

The basic word for organic came from the word organ

Where is the word of organic came from ………?

The study the compound of these elements

Therefore, organic chemistry is the study chemistry of carbon compounds, but also it also included the compounds containing, hydrogen, oxygen, nitrogen, and other elements such, halogen, phosphrous and sulphur, as shown in the following periodic table;

Examples Of Organic Compounds:

Compounsd Formula Elements Present

Benzene C6H6 C, H Vinegar CH3COOH C, H, O Sucrose C12H22O11 C, H, O Chloroform CHCl3 C, H, Cl Urea CO(NH2) C, H, O, N Protein(alanine) C3H7O2N C, H, O, N

Can any one in class explain what are some of the uses of the above compounds …….. ?

Before we discuss futher about the chemical bond, we should know of the following concept: 1. electronic configuration of an elements 2. Octet configuration

2,42.6

2s,2p1s

11Na 2,8,1

What is the electronic configuration meant….?

A particular arrangement of electron in the orbitals of an atom

J.McMurry p. 4

1H = 1S1 =

2He = 1S2 =

3Li = 1s22S1 =

4Be = 1s22S2 =

5B = 1s22S22p1 =

6C =1s22S22p2 =

7N =1s22S22p3 =

8O =1s22S22p4 =

9F =1s22S22p5 =

10Ne=1s22S22p6=

1S 2S 2p (pxpypz)

2.8 Octet

J.McMurry p. 5

1. Aluminium2. Cromium3. Manganese4. Copper

Write the configuration of the following elements

13Al = 1s2 2s2 2p6 3s2 3p1

24Cr = 1s2 2s2 2p6 3s2 3p6 4s13d5 ( x 4s2 3d4 )25Mn = 1s2 2s2 2p6 3s2 3p6 4s23d5

29Cu = 1s2 2s2 2p6 3s2 3p6 4s13d10 ( x 4s2 3d9 )

2 Filled > 2 half- filled > 1 filled 1 not half

Reaction between AB + C == > D Take place. Why ……. ?

The Chemical reaction take place inorder the system becomes:

1. More order …. ?2. More stable …. ?

AB + C

---------

AC + B

---------------E

Reaction Coordinate

H reaction

Atom at distance

Atom Bonded In Molecule

Energy

Ikatan Perkahwinan Menjadikan Individu Lebih Tenang/Stabil/Tersusun

Antara lelaki/perempuan

Antara lelaki/lelaki Antara Perempuan/perempuan

Stronger bonded

Weaker bonded

Covalent

Ionic/Heterovalent

1. Sharing electron among the elements ( covalent )2. Give/received the electron(s) == > ions3. Attraction between different ions ( ionic )4. Restructuring the electronic configuration in the

molecules Breaking down the bonds = (required energy) Rearrangement the pair(s) of electron(s)/Bonding Formation of new bonds (released energy)

A + A == > B (H+H ==> H2)AB+C == > A–C + B (H2+½ O2== > H2O)

Base on your experiences, can you name the types of bonding in chemistry ?.

There are:

1. Ionic bonding

2. Covalent bonding

3. Metallic bonding

4. Hydrogen bonding

By transfering/receiving an electron of electropositive and electronegative atoms

How does the ionic bond formed …..…. ?

Can any one in class explain it.. …………?

Electropositive element, (Na) gives up one valence electron, to have octet configuration and form a positive charge

Example Na (electropositive) and F (electronegative)

What is the configuration electron of Na atom ……?

11Na =

10Na+ = Octet Configuration “Stable”

J.McMurry m.s 7

Electronegatif element, (F) received one valence electron, to have octet configuration and form a negative charge

What is the configuration electron of F atom ? 9F =

10F- = Octet Configuration “Stable”

Na+ Na --- F F-

Electrostatic attraction Ionic bond

Ionic compound

Different charge Of (Na+) and (F-) attract together by electrostatic force to form ionic bond

Electropositive element Electronegative element ( Na ) 2.8.1 F ( 2.7 )

Give up 1 electron receive 1 electron

Na+ 2.8 (Octet/stable) Cl- ( 2.8 ) (octet/stable)

Different charge

Electrostatic force

Na --- F (Ionic Bonding

J.McMurry, p11

The word covalent is made up of two basic words, What are they …..?

They are CO + Valent ( valence )

What is the meaning of Co and valence ….. ?

Co meant sharing and valence related to valence electron

What is the meaning covalent bond than ….. ?

Bond formed by sharing of valence electron by any atoms so that each one atom to achieved an octet stable configuration ( Configuration od noble gas)

Example:

.. ..: F: : F : .. ..

F -- F

..H : O : H ..

H -- O -- H

..O :: C:: O ..

O = C = O

Electronic configuration for F = 1s2 2s2 2p5 Less one electron

J.McMurry, p11

Electronic configuration for Ne (noble gas) = 1s2 2s2 2p5

F atom would share one electron to another F atom to achived, octet (stable)configuration and form a covalent bond:

.. : F .

.. . F :

.. ..: F: : F :

F – F

Covalent Bond

Sharing electron

There are two types of covalent bonds; i) Sigma () bond ii) Pi ( ) bond

Is a covalent bond formed by orbitals overleapping end to end of the following orbitals:

i) two s orbitals ii) 1 s orbital and 1 p orbital iii) 2 p orbitals ( head-head or end-end )

What do you understand by sigma () bond………?

Its electron density is concentrated between the nuclei of the bonding atoms.

Study the following diagrams given

J.McMurry, p11

S orbital S orbital

S orbital p orbital

p orbitalp orbital

Electron density

Head-to head overleap Atomic Nucleous

Electron density

Does any one can explain what is pi () bond meant.…?

pi () bond is a covalen bond formed by overleapping of side-by-side of P orbitals.

Its electron density is concentrated above and below the plane of the nuclei of the bonding

Exame the following diagrams:

J.McMurry, p17

pz Orbital

px Orbital

py Orbital

Side by side overleap

Electron density

Electron Density

Draw the structure of 2-methyl-2-butene and identify the sigma () and pi () bond in the molecule

Also known as electron dot structure

A concept to show the structure of a molecule by using dots and dashes to show the valence electrons and shared pairs of the electrons

J.Mcmurry p, 8-9

Have you ever heard the terms “Lewis Structure” …. ?

Can any one give an example of a lewis Have you ever heard the terms “Lewis Structure” …. ?

Example: Hydrogen atom have 1 valence electrons. What is the lewis structure of carbon

Example: carbon atom have 4 valence electrons. What is the lewis structure of

carbon .. C . .

Example: one molecule of water was formed as result the combination

between 2 atoms of H and one atom of oxygen. H atom has 1 valence electron and oxygen have 6 valence eklectrons.

Can any one write the chemical and lewis structure of the above statement ?.

H2 + ½ o2 H2O

.. ..2H. + . O . H- O - H .. ..

Can any in class write the lewis structure of NH3?How many valence electron N have ……?

N have 5 valence electrons

. : N . .

Can any in class write valence electronic for N … ?

Now, Can any in class, write the lewis structure of NH3 H :

: N : H : H

or H I : N -– H I H

Please, write the lewis structure of the following molecules/compounds

i) Common salt

ii) Chloroform

iii) Ethanol

iv) Vinegar

What is the meaning of polar covalent bond …….?

What is/are the factors that determine covalent bond become a polar bond… ?

A bond in which electrons are not shared evenly (the density of the electron is not evenly distributed through the molecule and hence is a polar molecule

The electronegativity of the elements that form the covalent bond/molecule

Majority of the molecules are not 100% ionic nor 100% covalent

The molecules which not 100% ionic ( fully charge) or 100% covalent (electronically symmetrical) are called polar molecule (partially charge)

Example: Electrons are located more on F atom rather than in H ;Hel < Fel Hence at F is more negatif charge and at H is more positive charge; ..

H --- F : ..

When a covalent molecule formed between two different element having different electronegativity, such as:

H (2.1) and F ( 4.0)

the density of electron in both end of the molecules are not even. As result the polarity both end are different.

Different element have different electrogenativity, Example:

• Element Electronegativity

• H 2.1• Li 1.0

• Be 1.5• B 2.0

• C 2.5• N 3.0• O 3.5• F 4.0

Element Electronegativity Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0

The end with higher density of electron will be negative charge and the other end will positive charge

Or H ------ F ..H --- F : ..

The symbol + indicate partially (+) charge and - indicate partial (-) charge

The symbol --- > indicate the direction of polarization

If a molecules formed of different element hqaving different electronegativity the molecules should be polar.

Example

O-O, C-C, ( Less/not polar )

C- H, C- Cl, N - F, O-H, O-Cl ( polar )

At end of this disussion students should be able to:1. Define what hybridization is …. ?2. Explain how the formation of hybridization sp3 in

carbon3. Explain how the formation of hybridization sp2 in

carbon4. Explain how the formation of hybridization sp in

carbon

What do you meant by hybridization…… ?

Example: s orbital mix with 1 p orbital == > sp orbital

The mixing of different types of atomic orbital to produce a set of equivalent hybride orbital

J.Mcmurry p 12

s p sp

• There are 3 types of hybridization can occur in carbon:

• 1. Sp3 hybridization • 2. Sp2 hybridization• 3. Sp hybridization

What is the normal valence electrons of carbon in organic compounds?

Can you write the electronic configuration of carbon atom..?

What is the atomic number of carbon? six

1S2 2S2

2px2 2py 2pz

How many unpaired valence electron in the configuration available for bonding formation? Two (2)

four (4)

J.Mcmurry p 14

When carbon atoms, received enough energy, one electron from 2s orbital will move (jump) to 2py orbital, as shown, below:

How does the configuration electrons in carbon should change, inorder their valence electron becomes 4?

One of the electron from 2s orbital should move to py orbital

How?....

1s 2s 2px 2py 2pz

And now their electronic configuration becomes :

**Excited

How many unpaired electron available for formation bonding now that carbon atom have?

What is the angle between axis Px, Py and Pz90 o

Can any one of you draw the axis of p orbital ? How does its look like ?

1s 2s 2px 2py 2pz

1s orbital + 3 orbital p == > Hybride == > Sp3 orbital

If carbon atom using 3p atomic orbital for bonding, what should be the angle of the bonding? ……

Do you agree that most compouds involving carbon atom has bond angle of 90o? ….. What is your comman? ………

What is actually happen to the 4 unpaired electrons in carbon atom ? ………..

All four unpaired electrons are mix/combine together to form new 4 orbitals which equivalent each other

The process of transfer electron from s -- > p followed by the combine of four orbital to form special 4 equivalent orbital is known as Hybridization

The sp3 have following shape?

If not 90o, what should be the shape of the new orbital..?

= >sp3

The original S and p characteristic lose it identity

New identity orbitals is 4 new equilvalence orbital

special characteristic

Equivalent in angle,

Equivalent in bond strength

**Excited

s 3 pSp3 (tetrahedral)

H H HH

C ( sp3)Methane ( CH4 )

The 4 unpaired electron will shared by one electron each from hydrogen atom to form CH4

J.Mcmurry, p 18

As mentioned before, After 1 el (2s) move to 2p the electronic configuration in carbon atom becomes :

**Excited

1s orbital and 2 p orbital will hybrid each other to form sp2 hybrid;

How does the sp2 hybrid in carbon is form?

Can any one in class proposed … How the formation of Sp2 hybridization in carbon ? ……

1s 2s 2px 2py 2pz

J.Mcmurry p 16

Example:H2C=CH2

Overleaping 2 (C sp2)

Sp2 Sp2

Overleaping of 2 (Csp2)

H2C=CH2

As mentioned before, After 1 el (2s) move to 2p the electronic configuration in carbon atom becomes :

**Excited

1s orbital and 1 p orbital will hybrid each other to form sp hybrid;

How does the sp hybrid in carbon is form …..?

Can any one in class proposed … How the formation of sp hybridization in carbon ? ……

1s 2s 2px 2py 2pz

**Excited

1s 2s 2px 2py 2pz

Discuss the formation of hybridization in: i) NH3

ii) H2O

iii) BeCl2

• At end of this disussion students should be able to:

• 1. Discuss how a bond is beeing broken • 2. Discuss homolytic, heterolytic, nucleophile,

electrophile, carbocation and carboanion.• 3. Explain define distillation• 4. Explain the differences of simple distillation and

fractional distillation

In the chemical reaction the covalent bond beak by two ways:

i) Homolytic ii) Heterolytic

How does a covalent bond breaking in the chemical reaction…. ?

Let we discuss each types in relatively detail

A ¦ B === > A• + B• (Free radical)

So homolytic mean, a bond that break in an electronically symmetrical way, I.e:

It meant, one electron remains with each product fragment to form a free radical species, as shown below

What is the homolytic meant … ?

homolytic made up of homo (same) and lytic (loosing)… ?

What is the free radical ? Can any one give the definition of a radical .. ?

Radical is a species which have unpaired electron …..

Example:

CH4 == > CH3• + H • H H .. .. H : C : H ==> H :C. + H. .. .. H H

it is a reactive species

Radical is sp2 hybridized and planar

The orbital of radical is not empaty but it containsthe odd electron

So heterolytic is bond break down in an electronically unsymmetrical way

It meant that both electrons remain with one product fragment, living the other one with a vacant orbital

This process produced of a pair of ions, i.e; (cation and anion )

Can any one in class suggested the mechanism involved….?

What is the heterolytic meant … ?

heterolytic made up of hetero (different/not same) and lytic (loosing)… ?

A : B === > A+ + :B ( A: + B+ ) Ion ( cation/anion )

R – C -->-- X === > R– C + + X-

(Carbocation)/C’anion ( anion )

The mechanism of breaking down of the bond are given below:

If the process invloved carbon ( alkyl group ) a carbocation/carboanion is produce, as shown below:

Example: CH3 .. CH3

CH3 – C ---- Cl : === > CH3– C + + Cl-

CH3 .. CH3 (Carbocation) ( anion )

• - +• R – C --<-- MX === > R– C- + MX+

• (Carboanion) ( anion )

Example

• + -• (CH3)3– C : Cl === > (CH3)3– C+ + Cl-

• (Carbocation) ( anion )

Carbocation is also known as carbonium ion

What is carbonium ion…. ?

Carbonium ion is a species that contain a carbon atom bearing a positive charge

The (+) charge carbon atom is bonded to other atoms and it has no non-bonding electron.

It is sp2 hybridized with a planar structure and bond angles of about 120o

The unhybridized p orbital is vacant and lies perpendicular to the plane of the C-H bonds

Has only six electrons in its valence shell

At end of this discussion students should be able to:1. Define what is the carboanion 2. Define and give example of eletrophile and

nucleophile 3. State the differences of nucleo/electro phile4. Explain define distillation5. Explain the differences of simple distillation and

fractional distillation

Carboanion has a trivalent carbon atom that bears a (-) ve chargeThere are 8 electrons around the carbon atom ( 3 bonds and one lone pair )

It is a rich electronsIt is strong nucleophile ( lewis base )

The carbon atom is sp3 hybridized and tetrahedral in shape

One of the tetrahedral positions is occuoied by an unshared lone pair of electrons

What is the Carboanion ……?

Electron-deficient compounds have tendency to undergo chemical reaction inorder to complete their valence electron becomes octet. How … ?

Electron-deficient compound will react with a species (compound) that has one or more unshared valence electron pairs

Can any one give the example …. ? .. :F: F .. I .. :F -- B + [ : F ; ]- == > F – B -- F .. I .. I : F : F ..

In above reaction, the electron dedficient compound acts as a Lewis acid ( Electron acceptor )

The species that provides the electron pair act as Lewis bes. ( Electron donor )

In organic the lewis acid terms known as an electrophile and lewis bes known as nucleophile

.. :F: F .. I .. :F -- B + [ : F ; ]- == > F – B -- F .. I .. I : F : F ..

Lewis acid (electrophile)

Lewis bes (nucleophile)

What is electrophile meant .. ?

Electrophile made up of two words

( Electro + phile )

Electro mean is related with electron

Phile mean lovingLoving electron

What is nucleophile meant .. ?

Nucleophile made up of two words

( Nucleo + phile )

Nucleo mean is related with nuclei

Phile mean lovingLoving nuclei

H F H F

H N : + B F === > H N B F

H F H F

Nucleophile electrophile

.. H .. HCH3 – O : + H C Cl === > CH3 O C H + Cl-

.. H .. H Nucleophile electrophile

What do you understand of fractional distillation ……?

What do you meant of distillation ….?A process to separate a liquid mixture ( from liquid/ liquid) by boiling of the mixture in distilation apparatus.

G.I Brown, p 56

Fractional distillation is a procedure for separating liquid components of a solution that based on their different boiling points

2. Heating Mentel3. Flask

4. Fractionating column5. Condenser

6. Collection Bottle

1. Sampel

Sections Of Apparatus

Simple Distillation Fractional Distillation

Can you list out the differences between these two proceses…?

Gases B.P < 20oC, (C1-C4) hydrocarbon, used fuels & reactants to make plastics

Gasoline(napthas) 20-200oC (C5-C12) hydrocarbon, Used as motor fuels & Industrial solvents

Karosene 175-275oC (C12-C16) hydrocarbon, Used for lamp oil, diesel starting material for catalytic cracking,

Fuel oil 250-400oC (C15-C18) hydrocarbon, Used for catalytic cracking, heating oil, diesel fuel)

Lubricating oil < 350oC (C15-C20) hydrocarbon, Used as lubricatants),

Residue (asphalt) (>C20 hydrocarbon)

The more volatile fraction which consist of smaller molecules, are received from higher up the columm

Less volatile factions from lower columm

Fraction Temp oC No Of Carbon UseResidue >400 25 Heavy fuel oil & Butumen

Heavy Gas-oil light. 300-400 18-25 Fuel.Lubrication. Paraffin

Light Lubrication oil 300-400 Medicinal paraffin

Light gas-oil 250-300 13-17 Fuel oil Diesel enginers

Kerosine 190-250 11-14 Fuel oil (paraffin oil) Trctor & Jet-engines

Naphtha 100-200 Solvent & Raw material

Petrol (gasoline) 40-180 5-10 Fuel

Petroleum ether 40-60 Solvent 60-80

Gas Fraction < 40 1-5 Gaseous Fuel Source of Alkanes

G.I Brown, p 83-85

You are given a mixture containing C2H6, C10H22, C40H80. …Discuss how the mixture can be saperated ?

•Organic CompoundsHydrocarbon

Saturated Unsaturated

Straight Chain Cyclo Chain

Aromatic

Derivatives Of Hydrocarbon

Alkyl halides

Acid Halides

Ethers

Alcohols Aldehydes

Ketones Carboxylic Acids

amines

AcidamidesNitrilesAcid

Anhydrides

esters

(Aliphatic & Aromatic)

What is the functional group ……?

An atom (or group of atoms) that is part of a larger molecules and has a characteristic chemical reactivity.

The examples of functional group are given in the following table:

The functional group determine the chemical properties of the compound.

Compounds Fungsional gp G.Formula Example Alhyl Halide, Halogen RX CH3ClEther, -O- ROR CH3OCH3

Alcohol, -OH ROH CH3OHAldehyde, -CHO RCHO CH3CHOKetone, - CO - R-CO-R CH3COCH3

Carboxyalic acid, - COOH RCOOH CH3COOHEster - COO RCOOR CH3COOCH3

Amine, - NH2 RNH2 CH3 NH2

Amide -CONH2 RCONH2 CH3CONH2

Type Of Glass Composition (mass) Properties & Uses

Pure Quartz Glass 100 % SiO2 Low thermal expansion, Transparent (Optical research)

Pyrex Glass 60-80% SiO2, 10-25% B2O3, Littke Al2O3 Low thermal expansion, Transparent ( Lab Ware, House hold ware )

Soda-lime 12% Na2O, 12% CaO, 76% SIO2 Attck by chemical, Transparent, Sensitive to thermal shock ( Windo glass, Bottles)

Aluminosilicate 5% B2O3, 10% MgO, 10% CaO High Melting, (Cooking ware) 20% Al2O3, 55%SiO2

Lead alkali 10% Na2O, 20%PbO, 70% SIO2 High refractive index; (Lenses, Decorative glass)

Borosilicate 5% Na2O, 3% CaO, 16% B2O3, Low Coefficient of thermal expension; 76% SiO2 (Laboratory ware, cooking utensils

Bioglass 24% Na2O, 24% CaO, 6% P2O5, Compatible with bone,( Coating 46% SiO2 on srgical implants

R.Chang, p 460-462

Chap 1 Bonding

cooking utensils

high refractive

house hold

low thermal

pure quartz

terms lewis

cooking ware

low coefficient

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