Lesson Plan:Doing Lewis Dot Diagrams

Lesson Title: Doing Lewis Dot Diagrams
Topic/Focus Area: Chemistry

Lesson Overview
Content Standards
Objectives
Activities

Resources
File Attachments
Assessment
Additional Comments

Subject(s): Science

Grade Level(s): 11, 12

Name: Von Bowen
Taught: Chemistry
Phone:
E-mail: LBO@icoe.k12.ca.us

School: Southwest High

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Lesson Overview

Standards

Subject : Science
Grade : Nine thru Twelve
Strand : Chemistry
Substrand 1 : The periodic table displays the elements in increasing atomic number and shows how periodicity of the physical and chemical properties of the elements relates to atomic structure. As a basis for understanding this concept:

Atomic and Molecular Structure

Standard:

1d

Students know how to use the periodic table to determine the number of electrons available for bonding.

Standard:

1g*

Students know how to relate the position of an element in the periodic table to its quantum electron configuration and to its reactivity with other elements in the table.

Substrand 2 : Biological, chemical, and physical properties of matter result from the ability of atoms to form bonds from electrostatic forces between electrons and protons and between atoms and molecules. As a basis for understanding this concept:

Chemical Bonds

Standard:

2a

Students know atoms combine to form molecules by sharing electrons to form covalent or metallic bonds or by exchanging electrons to form ionic bonds.

Standard:

2b

Students know chemical bonds between atoms in molecules such as H₂ , CH₄ , NH₃ , H₂CCH₂ , N₂ , Cl₂ , and many large biological molecules are covalent.

Standard:

2e

Students know how to draw Lewis dot structures.

Student Learning Objectives

Students will construct a diagram of an atom,ion,or molecule in which the element symbol represents the nucleus and all inner level electrons while dots stand for outer level electrons.
Students will use the periodic table to determine the number of valence (outer) electrons of any atom.

Activities

DAY 1 1.Students will be given a pre-test, using a list of ten atoms, ions, and/or molecules, from which they are to give the electron configurations of the atoms and construct Lewis Dot Diagrams of each of the items.
DAY 1(cont)1.Students will observe a periodic table.
2. From the periodic table, students will determine the electron configuration of several elements.
3. Using this electron configuration, students will select the valence electrons (highest energy level electrons)of the elements.
4. Having selected the valence electrons, the students will draw the Lewis Dot Diagrams of the named atoms or ions.
DAYS 2 & 3 3. Students will construct, using an 8x5 index card, information about several elements. The information will include:name of element, symbol, atomic number, atomic mass, atomic and ionic diameters (2xr),first ionization energy, characteristics (structure,uses, hardness, color,etc),the electron configuration, and the Lewis Dot Diagram of the element. The students will work in groups of four, and each group will be responsible for constructing the information for one specific Group (family). These may be later used to build a complete student-designed periodic table.
Day 4 Give postquiz, which consists of the names only of ten different elements for which the students are asked to draw the correct Lewis Dot Structures.

Resources

Content Resources (books, articles, etc.)
Text

Overhead transparencies from Chemistry, 5th ed. Zumdahl

Web Resources
http://www.chemistrycoach.com/lewisflow.htm (www.chemistrycoach.com)

http://www.webelements.com/ (www.webelements.com)

http://www.anachem.umu.se/eks/pointers.htm- A compendium of chemistry resources. (www.anachem.umu.se)

http://www.chemicool.com (www.chemicool.com)

Hardware/Software Resources (computers, CD-ROMs, TV, VCR, etc.)
1. Computers
2. Document Camera or Overhead

digital camera

File Attachments

Lewis Dot pre-test
— pre-test.txt (204 bytes)

Lewis Dot postquiz
— postquiz.doc (19.5 KB)

student group cards
— IM000008.jpg (500 KB)

student individual cards
— IM000009.jpg (230 KB)

student sample A
— Student1.jpg (49.3 KB)

student sample B
— Student2.jpg (48.4 KB)

student sample C
— Student3.jpg (50.8 KB)

Assessment

Each student will be given a paper with ten atoms,ions,or molecules, and will be able to give the electron configuration of the atom or ion, and do a Lewis Electron Dot Structure of each of the items.
We will consider it a successful lesson if 80% of the students can accurately complete at least 8 of the ten items.

Additional Comments

A fairly simple method for writing Lewis structures:
1. Add the total valence electrons in the system
2. Count the total numer of electrons there will be if each atom has a full complement of electrons.
3. Subtract (1) from (2)
4. Divide the number by 2 (electrons per bond)
5. This will give you the number of bonds.
6. Draw the structure.
7. Exceptions include Be and B (may have fewer than 8) and third row and heavier elements may have more than 8.