Explorations of Reactivity

This teacher-driven lesson introduces students to the reactivity of elements mentioned in the previous lesson, "Mapping Trends" of the periodic table. This lesson includes demonstrations of chemical reactivity of several different elements. Students observe and record all observations for later discussion. The intent is that students walk away with a good understanding of (1)chemical changes of elements and (2) reactivity of elements as related to their position on the periodic table.

Physical Science: Atoms interact with one another by transferring or sharing electrons that are furthest from the nucleus. These outer electrons govern the chemical proeprties of the element.

Knowledge of the three states of matter and change in state, as well as a working definition of "reactivity."

a. Time frame: 90 minutes

b. Materials: Several elements, fuel source, and demonstration table.
Recommended elements include: Group IA elements demonstrating highly reactive elements, especially hydrogen and potassium; less reactive elements including carbon and iron; and intert elements, including helium.

c. Resouces: Periodic Tables previously prepared in the activity, "Mapping Trends" and chemistry textbooks.

d. Procedures/Strategies:
-Teacher-led discussion: The Teacher-student discussion should lead to common trends on the periodic table found in the earlier lesson, "Mapping Trends". The working term, "reactivity" and states of matter should be revisited here. Before demonstrations begin, students should be guided to record their observations for each demonstration in their learning logs (note-taking).
For information on learning logs, note-taking, and note-making see this site.
(http://www.sdcoe.k12.ca.us/score/actbank/tjournal.htm)

The teacher leads a class discussion about their observations. Teacher writes chemistry terms used by the students on the board.

Students choose from these terms and write a description on the reflection side of their learning logs.

-Teacher demonstrations: For chemical reaction demonstrations, the chosen elements should include elements that react at a fast rate, slow rate, and not at all during both oxidation-reduction reactions and acid/base reactions.

Recommended elements include: Group IA elements demonstrating highly reactive elements, especially hydrogen and potassium; less reactive elements including carbon and iron; and inert elements, including helium for no reaction.

-Individual Student Activity: Students write down observations for each demonstration. These observations will be shared with the entire class.
-Group Lab: Groups are given three "unknown" elements to test for reactivity. Based on their observations, students predict the locations of those elements on the periodic table. Post lab would include the teacher going over the unknown elements tested and their location.

Learning logs could be read for student understandings and misconceptions. Participation points could be given, as well.

For further research, students could relate the relative size of the atom to the reactivity of the atom. Electronegativity could be reasearched as well. Students could then prepare a graphic demonstrating their researched information for all students to observe and possibly map on the color coded periodic table (Mapping Trends).

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