Chemical Bonding & Electrical Conductivity

By Nicholas Harth • Megan Perkey

Grade Level	10th
Subject Area	Chemistry
Duration	2 days
Background Knowledge	At this point in their curriculum, the students were working through the Chemical Bonding unit in the ALICE (Active Learning In Chemistry Education) curriculum. They had been introduced to the various forms of chemical bonds through an exploratory internet activity that illustrated the concepts of ionic, covalent, polar covalent, and metallic bonds with two dogs sharing a bone. The students had also just started learning about Lewis Dot structures and various methods that are used when drawing bonds. They were extremely familiar with the periodic table of elements and could easily identify which elements are metals and which are non-metals.
Author	Nicholas Harth, Megan Perkey

Summary
During the first part of this activity, the worksheet serves as a conversation guide for the class. The teacher can lead the conversation and help the students to experiment with the different materials and even provide answers when necessary, but it is designed to be a group effort. This worksheet provides an opportunity for review and helps the students to understand the upcoming lab. In part two of the lesson, the students are asked to test a variety of liquids with the multi-meter in order to determine their resistivity. From there, they can calculate conductivity which is a property of ionic bonds. With these numbers, the students can rank the liquids according to bond strength and determine which material would be the best for use as an insulator and which would be the best as a conductor.

Objectives
1. To describe ionic and covalent bonds. 2. To identify the characteristics of ionic and covalent bonds. 3. To explain the electrical conductivity of ionic compounds. 4. To predict the bond type between two elements.

Mateirals Required
Attached worksheets,CaCl and a hammer, Rubber ball, Balloons, Digital Multimeters, A variety of chemical solutions

Ohio Standards

Science:

1. Describe the identifiable physical properties of substances (e.g. conductivity). Explain how changes in these properties can occur without changing the chemical nature of the substance.
2. Compare the conductivity of different materials and explain the role of electrons in the ability to conduct electricity.
3. Identify a problem or need, propose designs and choose among alternative solutions for the problem.
4. Draw conclusions from inquiries based on scientific knowledge and principles, the use of logic and evidence (data) from investigations.

Technology:

1. Produce graphs and/or charts to describe trends and visualize data.