Mme 323 materials science week 2 - atomic structure & interatomic bonding

MME 323: MATERIALS SCIENCE WEEK 2 :

ATOMIC STRUCTURE & INTERATOMICBONDING*

Adhi Primartomo, PhDEmail: [email protected]: Room 191 – JIC Academic Building* Source: Materials Science and Engineering; 9th Edition; W.D.Callister;

Wiley; 2011

https://sites.google.com/site/primartomo/file-cabinet

~ LECTURE OUTLINE ~

Chapter 2: Atomic Structure & Interatomic Bonding (page 17 - 43)

• Why Study Atomic Structure & Interatomic Bonding?

• Fundamental Concepts,

• Electrons in Atoms,

• Quantum Numbers,

• Electron Configuration,

• The Periodic Table,

• Primary Atomic Bonding,

• Secondary Atomic Bonding.

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~ Week 2 Learning Objective ~

After studying this chapter, you should be able to:

• Define atomic number, atomic mass, isotope, atomic weight and atomic mass unit,

• Name the two atomic models and note the differences between them,

• Give the atomic configurations for the atoms based on Pauli exclusion principle,

• Briefly describe the ionic, covalent, metallic, hydrogen and Van der Waals bonds,

• Mention which atoms/molecules exhibit each of these bonding types mentioned above.

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WHY STUDY ATOMIC STRUCTURE & INTERATOMIC BONDING?

(page 18)

The atomic structures and interatomic bonding directly define the properties of materials

4

Pic Source:http://www.auburn.edu/~blumeri/diamond/diamond.htm

Example: Carbon as graphite and diamond

FUNDAMENTAL CONCEPTS(page 18-19)

Atom consist of:

Nucleus (core): protons + neutrons

Electrons (e-)

5

• Atomic Number (Z):

?

• Atomic Mass (A):

?

• Atomic Weight:

?

• Atomic Mass Unit (amu):

?

• Isotope:

?

ELECTRONS in ATOMS – ATOMIC MODELS(page 20-21)

Bohr Atomic Model:

Electrons revolve around nucleus in certain orbitals

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Wave Mechanical/Quantum Mechanics Model:

Electrons is at various locations around nucleus

The locations/regions shapes is described by complex mathematical equations

ELECTRONS in ATOMS – QUANTUM NUMBERS(page 21-23)

7

• Every electron in an atom is characterized by 4 parameters

Quantum Numbers (n, l, m, no. of electrons)

• ‘n’ no. of shells

Value of ‘n’ = 1 ,2 ,3 & 4

• ‘l’ no. of sub-shells

Value of ‘l’ = 0 ,1 ,2 & 3 or s, p, d & f

value of 'n' value of 'l' Name of Subshell

1 0 (s) 1s

20 (s) 2s

1 (p) 2p

3

0 (s) 3s

1 (p) 3p

2 (d) 3d

4

0 (s) 4s

1 (p) 4p

2 (d) 4d

3 (f) 4f

ELECTRONS in ATOMS – QUANTUM NUMBERS(page 21-23)

8

• ‘m’ no. of electron orbitals in each sub-shell

• Each electron orbital max 2 electrons

Subshell No. of Orbitals (m) Max No. of Electrons

s 1 2

p 3 6

d 5 10

f 7 14

Shell No.: Name of Subshell + Max Electrons

1 1s2

22s2

2p6

3

3s2

3p6

3d10

4

4s2

4p6

4d10

4f14

ELECTRONS in ATOMS – ELECTRON CONFIGURATIONS(page 24-26)

9

• Pauli Exclusion Principle each electron state/electron orbital

max 2 electrons

Subshell No. of Orbitals (m) Max No. of Electrons

s 1 2

p 3 6

d 5 10

f 7 14

Shell No.: Name of Subshell + Max Electrons

1 1s2

22s2

2p6

3

3s2

3p6

3d10

4

4s2

4p6

4d10

4f12

10

1s

2s2p

K-shell n = 1

L-shell n = 2

3s3p M-shell n = 3

3d

4s

4p4d

Energy

N-shell n = 4

• have discrete energy states• tend to occupy lowest available energy

state.

Electrons:


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Hafnium Diagonal Rule for Electron Configuration:



12

• Electron Configuration represents the way in which the

electron states/electron orbitals are occupied.

• Notation (how to write) : No. of electrons in each subshell indicate by a script after shell-subshell designation:

1s2

Shell Subshell

No. of electron

• Examples: - Hydrogen (H), Z=1 1s1

- Helium (He), Z=2 1s2

- Lithium (Li), Z=3 1s2 2s1


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Valence electron:

• Electrons that occupy outermost shell,

• Involve in bonding between atoms to form molecules,

• Physical & chemical properties of solids based on valence electron.

Stable electron configuration:

• Valence electron shell completely filled,

• Max no. of electron in outermost shell 8 (as in Ne, Ar, Kr)

• Basic for chemical reactions & atomic bonding in solids ?

THE PERIODIC TABLE of ELEMENTS(page 26-27)

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• Element Type of Atom that is distinguishes by Its Atomic

Number • Periodic Table of Elements Tabular Method of Displaying

Elements• Same Column Same valence electron and similar properties Alkali Metal –> Group 1 (Li, Na, K, Rb, Cs): Soft, Low Density,

Has 1 valence electron Very Reactive (React with halogen) Halogen –> Group VIIA (F, Cl, Br, I): Has 7 valence electrons Highly Reactive Gas (React with Alkali Metal)

Noble Gas –> Group VIIIA (He, Ne, Ar, Kr, Xe): Odorless, Has 8valence electrons Great Chemical Stability

Electropositive ? Electonegative ?

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THE PERIODIC TABLE of ELEMENTS(page 26-27)

PRIMARY INTERATOMIC BONDINGS(page 30-37)

Atom-to-Atom bonding that involves the exchange of valence electrons to assume stable electrons structure (as inert gases – 8

valence electrons

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1. Ionic Bonding • metal + non-metal, electropositive + electronegative• ?

PRIMARY INTERATOMIC BONDS(page 30-37)

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2. Covalent Bonding • Non-metal + non-metal,• ?

PRIMARY INTERATOMIC BONDS(page 30-37)

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3. Metallic Bonding • metal + metal,• ?

SECONDARY BONDING(page 30-37)

Arise due to atomic or molecular dipoles

19

1. Van der Waals bonding:

SECONDARY BONDING(page 30-37)

Arise due to atomic or molecular dipoles

20

2. Hydrogen Bonding:

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Education

Mme 323 materials science week 2 - atomic structure & interatomic bonding