chemical bonding n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chemical Bonding PowerPoint Presentation
Download Presentation
Chemical Bonding

Loading in 2 Seconds...

play fullscreen
1 / 23

Chemical Bonding - PowerPoint PPT Presentation


  • 78 Views
  • Uploaded on

CHEMISTRY - DMCU 1233. Fakulti Kejuruteraan Mekanikal, UTeM. Lecturer: IMRAN SYAKIR BIN MOHAMAD MOHD HAIZAL BIN MOHD HUSIN NONA MERRY MERPATI MITAN. Chemical Bonding. Chapter 5. THE STABILITY OF NOBLE GAS STRUCTURE. Noble gases consist of the elements helium, neon, argon, krypton,

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chemical Bonding' - lawrence-miles


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
chemical bonding

CHEMISTRY - DMCU 1233

Fakulti Kejuruteraan Mekanikal, UTeM

Lecturer:

IMRAN SYAKIR BIN MOHAMAD

MOHD HAIZAL BIN MOHD HUSIN

NONA MERRY MERPATI MITAN

Chemical Bonding

Chapter 5

slide2

THE STABILITY OF NOBLE GAS STRUCTURE

Noble gases consist of the elements helium, neon, argon, krypton,

xenon, and radon

  • Characterised by completely filled “s”and “p” sub shells.
  • All gases except helium (it has 1s2 configuration) have stable s2p6 electron configuration or eight electrons in their outer most shell
  • Noble gases have stable electron configuration, making them extremely unreactive elements
slide3

THE OCTET RULE

Octet rule defines that atoms tend to gain, lose or share electrons

until they are surrounded by eight valence electrons

  • Most elements in the periodic table tend to undergo reactions to obtain eight outer-shell electrons or the stable electron configuration of the noble gases.
  • The atoms of these elements may gain, lose or share electrons to obtain this stable configuration
slide4

Group

e- configuration

# of valence e-

ns1

1

1A

2A

ns2

2

3A

ns2np1

3

4A

ns2np2

4

5A

ns2np3

5

6A

ns2np4

6

7A

ns2np5

7

Valence electrons are the outer shell electrons of an atom. The valence electrons are the electrons that participate in chemical bonding.

slide6

-

-

-

-

+

Li+

Li

Li

Li+ + e-

e- +

Li+

Li+ +

F

F

F

F

F

F

The Ionic Bond (Electrovalence)

An Ionic bond is the electrostatic force that holds ions together

in an ionic compound

Ionic compound combine a Group IA & Group IIA metal with

a halogen or oxygen

[He]

[Ne]

1s22s1

1s22s22p5

1s2

1s22s22p6

slide7

Why should two atoms share electrons?

+

8e-

7e-

7e-

8e-

F

F

F

F

F

F

F

F

lone pairs

lone pairs

single covalent bond

single covalent bond

lone pairs

lone pairs

The Covalent Bond

A covalent bond is a chemical bond in which two or more electrons are shared by two atoms. (Non metal & non metal)

Lewis structure of F2

slide8

single covalent bonds

H

H

H

H

or

H

H

O

2e-

2e-

O

8e-

O

C

O

C

O

O

double bonds

8e-

8e-

8e-

double bonds

O

N

N

triple bond

N

N

triple bond

8e-

8e-

Lewis structure of water

+

+

Double bond – two atoms share two pairs of electrons

or

Triple bond – two atoms share three pairs of electrons

or

slide9

Lengths of Covalent Bonds

Bond Lengths

Triple bond < Double Bond < Single Bond

slide11

F

H

F

H

Polar covalent bond or polar bond is a covalent bond with greater electron density around one of the two atoms

electron rich

region

electron poor

region

e- poor

e- rich

d+

d-

slide12

Electronegativityis the ability of an atom to attract toward itself the electrons in a chemical bond.

Electron Affinity - measurable, Cl is highest

Electronegativity - relative, F is highest

Both are related but different concepts. EA refers to an isolated atom and E refers to an atom in chemical bond. Usually, EA > then E >.

slide14

0

Covalent

 2

Ionic

0 < and <2

Polar Covalent

Increasing difference in electronegativity

Covalent

Polar Covalent

Ionic

partial transfer of e-

share e-

transfer e-

Classification of bonds by difference in electronegativity

Difference

Bond Type

slide15

Classify the following bonds as ionic, polar covalent,

or covalent: The bond in CsCl; the bond in H2S; and

the NN bond in H2NNH2.

slide16

Generally, intermolecular forces are much weaker than intramolecular forces.

Intermolecular Forces

Intermolecular forces are attractive forces between molecules.

Intramolecular forces hold atoms together in a molecule.

  • Intermolecular vs Intramolecular
  • 41 kJ to vaporize 1 mole of water (inter)
  • 930 kJ to break all O-H bonds in 1 mole of water (intra)

“Measure” of intermolecular force

boiling point

melting point

DHvap

slide17

Orientation of Polar Molecules in a Solid

Intermolecular Forces

Dipole-Dipole Forces

Attractive forces between polar molecules

slide18

Ion-Dipole Interaction

Intermolecular Forces

Ion-Dipole Forces

Attractive forces between an ion and a polar molecule

slide19

Intermolecular Forces

Dispersion Forces (London)

Attractive forces that arise as a result of temporary dipoles induced in atoms or molecules

ion-induced dipole interaction

dipole-induced dipole interaction

slide20

Dispersion forces usually increase with molar mass.

Intermolecular Forces

Dispersion Forces Continued

Polarizability is the ease with which the electron distribution in the atom or molecule can be distorted.

  • Polarizability increases with:
  • greater number of electrons
  • more diffuse electron cloud
slide22

Intermolecular Forces

Hydrogen Bond

The hydrogen bond is a special dipole-dipole interaction between they hydrogen atom in a polar N-H, O-H, or F-H bond and an electronegative O, N, or F atom.

A H--B

or

A H--A

A & B are N, O, or F

slide23

Decreasing molar mass

Decreasing boiling point

Why is the hydrogen bond considered a “special”

dipole-dipole interaction?