Teacher Notes for Science ATC Teacher Notes for Science ATC lesson on Sept. 13,2011lesson on Sept. 13,2011

Lesson Objective: 10Lesson Objective: 10thth grade ATC grade ATC students will draw Lewis Electron Dot students will draw Lewis Electron Dot structures for various elements on the structures for various elements on the periodic tableperiodic table

Please have the students go over the Please have the students go over the Power Point provided. On a notebook Power Point provided. On a notebook sheet of paper, they will draw and sheet of paper, they will draw and complete the chart shown on the complete the chart shown on the presentation.presentation.

Science ATC Lesson for Science ATC Lesson for September 13, 2011September 13, 2011

Lewis Electron Dot Structure

Essential Question: What is a Essential Question: What is a Lewis Electron dot structure?Lewis Electron dot structure?

DefinitionDefinition: An atom’s Lewis : An atom’s Lewis electron dot structure consists of the electron dot structure consists of the element’s symbolelement’s symbol, which represents , which represents the atomic nucleus and inner-level the atomic nucleus and inner-level electrons, electrons, surrounded by dotssurrounded by dots representingrepresenting the atom’s the atom’s valence valence electronselectrons..

Source: Glencoe Chemistry Matter and Change pg. 140

Group 1A: 1 valence electron

How do we use the periodic table to draw Lewis electron dot structures?Identifying the representative group

number will allow you to determine the number of valence electrons.

Here’s how….

Group 2A: 2 valence electrons

Group 3A: 3 valence electrons

Group 4A: 4 valence electrons

Group 5A: 5 valence electrons

Group 6A: 6 valence electrons

Group 7A: 7 valence electrons

Group 8A: 8 valence electrons

What’s Next????What’s Next???? Once you have identified the group number for Once you have identified the group number for

that element, then you know how many valence that element, then you know how many valence electrons it has. electrons it has.

Example: Nitrogen is on group 5A, so it has 5 Example: Nitrogen is on group 5A, so it has 5 valence electrons. valence electrons.

NStep 1: write the element symbol.

Step 2: Start on the top of the symbol and place one electron at a time on the four sides of the symbol and then pair up until all are used.

Your Turn:Your Turn: Draw and complete a chart, such as the Draw and complete a chart, such as the

one you see below.one you see below. Element Element NameName

Element Element SymbolSymbol

# of # of valence valence e-e-

Lewis Lewis Electron Electron Dot Dot StructureStructure

sodiumsodium

calciumcalcium

boronboron

tintin

arsenicarsenic

oxygenoxygen

brominebromine

neonneon

RememberRemember

If you have additional questions, If you have additional questions, please contact your local El Dorado please contact your local El Dorado Science Teacher.Science Teacher.

In addition, you may always refer to your In addition, you may always refer to your text book: Glencoe Chemistry Matter and text book: Glencoe Chemistry Matter and Change pg. 140 (Electron dot notation)Change pg. 140 (Electron dot notation)