St. George's College
Subject: 8th CHEMISTRY
Teacher's notes
Objectives
Class: Chemical Bonding
Vocabulary Link and Learn
Date: August 24th
2009
In‐Class Survey
Prepared by
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8th Milton A ‐ Chemical Bonding Name
Oral Intervention
Sergio María Fernanda Alejandra Almendra Anna Paula Sandra E‐C Maia María Belén Alfredo Kinley Arianne Sandra M. Fiorella Rodrigo Giulia Jaime Stefano Bruno
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8th Milton Alpha ‐ Chemical Bonding Name
Oral Intervention
Marcelo Antonella Paulo Alejandro Brenda Diego Gabriel Valeria Cristina Giuliana Joshua María Gracia Gonzalo N. Paolo Gonzalo R. Giorgio Nicolás María Claudia
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Let's remember previous learned concepts...
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ENERGY LEVELS • Electrons move around the nucleus (negative charge around positive charge). • Even though it looks as if this movement is disorganized, in fact there is a strict organization of the electrons. • Electrons move around the nucleus packed in Energy Levels. • Energy levels are the "layers" around the nucleus where electrons are found in motion. • These energy levels are called Electron shells.
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Rules to fill up the Electron Shells 1. The first electron shell, the closest to the nucleus can hold up to 2 electrons. 2. The other electron shells can hold many more electrons. 3. The last electron shell can only hold up to 8 electrons, this is called the Octet Rule.
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Gilbert Newton Lewis • American physical‐chemist that published "The Atom and the Molecule". • He is known for the description of the atomic dot diagrams, discovery of the Covalent Bond, description of the Lewis Acid‐ Base definitions, and the discovery of the photon as the minimum unit of radiant energy.
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Dot Diagrams • The electrons located in the last energy level of atoms are called Valence Electrons. • These electrons are easily recognized when checking the group the atom belongs to in the periodic table. • The valence electrons are represented by dots or crosses. • The elements must comply with the Octet Rule., and is used only for single elements or covalent compounds
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Examples
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New knowledge beginning......
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Combining Atoms • All substances are made of atoms of one or more of the 100+ elements. • Chemical bonding is the joining of atoms to form new substances. • The properties of these new substances are different from the properties of the original elements. • An interaction that holds two atoms together is called a chemical bond. • When chemical bonds form, electrons are shared, gained or lost.
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Electron Number • The number of electrons in an atom can be determined by the atomic number (number of protons). As long as the atom is neutral, with no charge, the atomic number will be the number of electrons. • The electrons in an atom are organized in energy levels.
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4p 3d
E N E R G Y
4s
3p 3s
2p 2s 1s 13
Valence Electrons • Not all the electrons in an atom make chemical bonds. • Most atoms form bonds using only the electrons in the outermost energy level. • An electron in the outermost energy level of an atom is a valence electron.
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Bonding • Not all atoms bond in the same manner. In fact, some rarely bond at all. • The number of electrons in the outermost energy level of an atom determines whether an atom will form bonds. • Having 8 valence electrons is a special condition, these atoms do not usually form bonds, because they are stable atoms.
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Resources Used Slide (Group)
Description
Resource
Origin
G1 ‐ 2
Image
Milton
http://bit.ly/XQqEw
G1 ‐ 3
Image
Milton
http://bit.ly/XQqEw
G1 ‐ 4 Animation Idea
Notebook Gallery
G1 ‐ 6
Images
Electron Shells
http://bit.ly/3Rksdj
G1 ‐ 7
Image
Gilbert Lewis
http://bit.ly/JUcpU
G1 ‐ 8
Animation Example 1
G1 ‐ 9 Images
Dot Diagrams
http://tinyurl.com/l8lsw5 http://tinyurl.com/l8lsw5
G1 ‐ 10 Animation Check this out
Notebook Gallery
G1 ‐ 11 Images
http://tinyurl.com/mkqeo9 http://tinyurl.com/mc33kn
Chemical Bonding 1 Chemical Bonding 2
G1 ‐ 12 Animation NaCl
http://tinyurl.com/l9hjqn
G1 ‐ 14 Image
http://tinyurl.com/mrdvyl
Valence Electrons
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Teacher's Notes This class has been designed to cover the topics of Chemical Bonding from Monday August 24th till Friday August 28th. For further knowledge about this topic: 1. Conduct a thorough search under the topic: Chemical Bonding on the Web, books and magazines. 2. If findings are not specific, ask your teacher for suggestions.
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Objectives • Identify and describe the properties and characteristics of Chemical Bonding. • Review and recognize compounds with different types of bonding, and compare their physical properties.
Note: All, or most, of the objectives will be covered during class time, however the student must be responsible for those objectives not covered or concluded.
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Vocabulary • • • • • • •
Electron: Energy Level: Octet Rule: Ionic bonding: Covalent bonding: Metallic bonding: Crystalline network:
Note: Most of the vocabulary words will be covered during class time, however the student must be responsible for those words not covered or concluded.
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Link and Learn You can visit the following websites to improve your understanding on the present topic: • • • • •
http://www.chemguide.co.uk/atoms/bonding/ionic.html http://tinyurl.com/8yb6b http://science‐learning2009.wikispaces.com http://learningandscience.blogspot.com http://libraryatstgeorge.blogspot.com
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Prepared by
Gerardo LAZARO Science Lead Teacher Email: glazaro@sanjorge.edu.pe Wiki: http://science‐learning2009.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro
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SURVEY If you want to contribute in improving your Chemistry class, click in the survey link:
Term III ‐ 8th A ‐ Class 3 Term III ‐ 8th Alpha ‐ Class 3
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Term III Class 2 Chemical Bonding
Grade: Subject: Date:
8th Grade Chemistry A August 24th, 2009
25
What was your UNDERSTANDING of the topic: "Chemical Bonding"
1
A
I understood 25% of the whole topic
B
I understood 50% of the whole topic
C
I understood 75% of the whole topic
D
I understood 100% of the whole topic
E
I didn't understand the class
26
2
What was your level of EFFORT to understand the topic?
A
My effort level was 25%
B
My effort level was 50%
C
My effort level was 75%
D
My effort level was 100%
E
I didn't put any effort
27
3
What RESOURCES helped you understand the topic? A
Text
B
Images
C
Animations
D
Videos
E
Teacher's Speech
F
None
G
Other
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4
How does the SMART Board help you understand the topic?
A
It helps me visualize concepts
B
It helps understand difficult concepts
C
Touching things helps me learn
D
Interacting with the information makes it easier to understand
E
I prefer less effects or audiovisual resources
F
It doesn't really help much
G
I don't like it
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Term III Class 2 Chemical Bonding
Grade: Subject: Date:
8th Grade Chemistry Alpha August 24th, 2009
30
What was your UNDERSTANDING of the topic: "Chemical Bonding"?
1
A
I understood 25% of the whole topic
B
I understood 50% of the whole topic
C
I understood 75% of the whole topic
D
I understood 100% of the whole topic
E
I didn't understand the class
31
2
What was your level of EFFORT to understand the topic?
A
My effort level was 25%
B
My effort level was 50%
C
My effort level was 75%
D
My effort level was 100%
E
I didn't put any effort
32
3
What RESOURCES helped you understand the topic? A
Text
B
Images
C
Animations
D
Videos
E
Teacher's Speech
F
None
G
Other
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4
How does the SMART Board help you understand the topic?
A
It helps me visualize concepts
B
It helps understand difficult concepts
C
Touching things helps me learn
D
Interacting with the information makes it easier to understand
E
I prefer less effects or audiovisual resources
F
It doesn't really help much
G
I don't like it
34