© GNU Su-Jin Kim

Atomic Bonding

Material Science

Material Science

Atomic Bonding

(원자결합)

Professor Su-Jin Kim

Gyeongsang National University

© GNU Su-Jin Kim

Atomic Bonding

Material Science

OCW

3. Atomic Bonding

https://www.youtube.com/watch?v=jBSHhtzZeSA&list=PL8EAOgbez9XIWGbmcihctMO4bXSB4V8hm&index=3

4. Interatomic Forces & Energy Curves

https://www.youtube.com/watch?v=mk0c0ztofNY&index=4&list=PL8EAOgbez9XIWGbmcihctMO4bXSB4V8hm

1. Ionic Bond https://youtu.be/dqW7H7c7M4A

2. Covalent Bond https://youtu.be/ZxWmyZmwXtA

3. Metallic Bonds https://youtu.be/vOuFTuvf4qk

© GNU Su-Jin Kim

Atomic Bonding

Material Science

KOCW

2. 원자결합과물성

http://www.kocw.net/home/cview.do?lid=3001880c1efe1f03

http://www.kocw.net/home/cview.do?lid=cb94c140315559ad

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Solid Materials주기율표

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Atomic bonding

• Why? Lower their overall energy happens at particular spacing between atoms.

• 3 types of primary bonding

1. Ionic: metal & non-metal, transfer of electrons

2. Covalent: sharing of electrons

3. Metallic: valence electrons drift through entire metal (sea of electrons)

• 2ndary : Vader waals bonding

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Ionic bonding (이온결합)

• Metal & non-metal, transfer of electrons

• Metal donate electro to non-metal

• Hard , Insulators, Transparent, Brittle, Melting point↑

Sodium + Chlorine

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Covalent bonding (공유결합)

• Sharing of electrons: both atoms share outer electron shells.

• Directional bonding

• Hard , Insulators, Transparent, Brittle

Carbon 2C + hydrogen 4H

C

-

-

--

H

-

H

-

H

-

H

-

Ethene C2H4

C

- -

- -

- -

H

H

C

- -

- -

- -

H

H

C

- -

- -

- -

H

H

Polyethylene -[C2H4]n-

C

-

-

--

C

- -

- -

- -

H

H

C

- -

- -

- -

H

H

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Metallic bonding (금속결합)

• Valence electrons drift through entire metal (sea of electrons)

• The outer electrons of metal leave individual atoms to become part of common “electron cloud”

• Electrical and thermal conductors, Opaque, Ductile

+ + + +

+ + + +

+ + + +

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Van der Waals bonding (2차결합)

• Due to the Interaction between molecules called intermolecular force. It is much weaker than covalent bonding.

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

Covalent bonding

Van der Waals bonding

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Atomic Bonding Energy

Interatomic separation r

Attractive energy EA

Repulsive energy ER

Pote

ntial energ

y E

Repuls

ion

Attra

ction

0

-

+

Net energy EN

© GNU Su-Jin Kim

Atomic Bonding

Material Science

Summary

Type Bond energy Direction Material

Ionic Large Non-directional Ceramic

CovalentVariablelarge-Diamondsmall-Bismuth

DirectionalCeramic, Semiconductor,Polymer chain

MetallicVariablelarge-Tungstensmall-Mercury

Non-directional Metal

Secondary smallest Directional Polymer