Classification of the Chemical Elements

Purham, James Chicago Vocational High School

Objectives: 1. The students will learn how the chemical elements are arranged on the PERIODIC TABLE. 2. Given adequate information, students will be able to arrange the elements on the PERIODIC TABLE. 3. Students will learn about some of the important chemical and physical properties of the elements. Apparatus Needed: One board that is approximately one meter square for every five students, piece of felt material that is large enough to cover each board, felt material of several different colors to be used as elements, stick pins to anchor felt strips to board, lineless white paper and stapler. Preparation; 1. Cover each board with a piece of felt material. One board per five students is suggested. 2. Draw an outline of PERIODIC TABLE on felt material that is attached to each board. 3. Cut several strips of felt material of different colors. Individual strips of felt material should be small enough to fit into the boxes on the PERIODIC TABLE. 4. Cut strips of lineless paper about the same size as the felt strip. 5. On strips of paper, write enough description of the elements so that students can locate the positions of the elements on the PERIODIC TABLE. 6. Strips should also be cut for first exercise using the chart. Do not attach anything to these felt strips. NOTE: FELT STRIPS OF THE SAME COLOR SHOULD BE MADE FOR ALL ELEMENTS THAT ARE IN THE SAME FAMILY. Recommended Strategy: 1. Give a brief introduction to the PERIODIC TABLE, such as the importance and some of the problems that were encountered in arranging the elements in a scientific manner. 2. Introduce the terms FAMILY, GROUP, PERIOD and SERIES. 3. Distribute PERIODIC TABLES and several strips of different colors that have nothing attached to them. Ask students to arrange felt strips in what they consider to be an orderly manner. Allow about five minutes for this exercise. Each group will probably have the strips arranged in a different way. The purpose of having the students to arrange the strips, is to dramatize some of the
problems that were experienced in agreeing on a way to arrange the
elements on the table.
4. Discuss the following: triad system, octave system, Mendeleev's
periodic table, variation of metallic and nonmetallic properties of
the elements in a family and a period; variation of the size of the
elements in a family and a period; variation of electron affinity of
the elements in a family and a period; variation of the ionization
of the elements in a family and a period; and variation of
electronegativity in a family and a period.
5. Pass out elements (felt strips) on which descriptions have been
attached and instruct the students to arrange them on the chart,
based on the information that was given during the lecture.
6. After adequate time has been given for students to place elements on
the table, ask students to describe the most unique things they
noticed about the table.
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