8th Chemistry - Valence Electrons

St. George's College Subject: 8th CHEMISTRY

Teacher's notes

Objectives

Class:

Vocabulary

Valence Electrons

Link and Learn

Prepared by

Date: June 1st

2009 1

8th Milton A ‐ Valence Electrons Name

Oral Intervention

Coin

Chocolate

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 ‐ Valence Electrons Name

Oral Intervention

Coin

Chocolate

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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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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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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VALENCE ELECTRONS • These are the electrons located in the last energy level or outermost electron shell.

• These are the electrons that interact with other atoms.

• Let's remember, Why do atoms interact with other atoms?

"s" block

"p" block

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VALENCE ELECTRONS • When atoms combine into compounds then try to complete their outer shells.

• Because atoms always look to fill the last electron shells with 8 electrons, complying with the Octet rule.

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ATOMIC BONDING • Atoms bond together with other atoms in a chemical reaction top make a compound.

• This reactivity is due to the electron arrangements in atoms.

• If atoms have incomplete electron shells they will usually react with other atoms.

• Only atoms with complete electron shells tend to be unreactive (Noble Gases).

• When atoms combine they try to achieve full outer electron shells.

• They do this either by gaining electrons to fill the gaps in the outer shell or by losing electrons from the outer shell to leave an inner complete shell.

• There are two different ways in which atoms can bond together: Ionic bonding and Covalent bonding.

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Exercises • Determine the Valence Electrons of the following elements and determine their dot diagrams:

Aluminum Germanium Antimonium Polonium Magnesium Chlorine Argon

x

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K-W-L Chart What I KNOW about this topic

What I WANT to know about this topic

What I LERANED about this topic

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SURVEY If you want to contribute in improving your Chemistry class, click in the survey link:

Google Forms Term II ‐ 8th Chemistry ‐ Class 3

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Resources Used Slide (Group)

Description

Resource

Origin

G1 ‐ 2

Image

Beethoven

http://bit.ly/Q7ggk

G1 ‐ 3

Image

Mozart

http://bit.ly/18LkW6

Idea

Notebook Gallery

See Saw Rule

Notebook Gallery

G1 ‐ 6 Image

Electron Shells

http://bit.ly/bJUj

G1 ‐ 8 Image

Gilbert Lewis

http://bit.ly/JUcpU

G1 ‐ 9 Image

Orbitals "d"

http://bit.ly/Jyo1n

G1 ‐ 10 Image

Orbitals "f"

http://bit.ly/Jyo1n

G1 ‐ 12 Animation

Periodic Table

Notebook Gallery

G1 ‐ 4 Animation G1 ‐ 5

Animation

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Teacher's Notes This class has been designed to cover the topics of Valence Electrons from Monday June 1st till Friday June 5th.

For further knowledge about this topic: 1. Conduct a thorough search under the topic: Valence Electrons on the Web, books and magazines.

2. If findings are not specific, ask your teacher for suggestions.

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Objectives • Understand the distribution of outermost electrons (valence electrons) in elements.

• Describe the properties of chemical elements due to their number of valence electrons.

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 • • • • • • •

Quantum Numbers: Orbitals: Electrons: Octet Rule: Dot Diagram: Valence: Bond:

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://bit.ly/hLE1o 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‐learning.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro

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