Classification of the Chemical Elements

Purham, James                       Chicago Vocational High School      
                                    933-8100
                          

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.