Puzzles for Teaching Descriptive Chemistry Mildred H. Evans Erie Community College, 4140 Southwestern Boulevard, Orchard Park, NY 14127
Given the large amount of material to be covered in freshman general chemistry, descriptive chemistry had become somewhat neglected; however, recently an effort has been made to include more descriptive chemistry. In a course already packed with more material than is comfortable to cover in two semesters how is one to cover additional material? One answer to this problem is to encourage students to cover some of the material on their own without taking class time. I have achieved some measure of success in doing this via crossword puzzles. Given a crossword puzzle to do with clues taken from a given chapter or set of chapters forces the student toread the chapterb) looking for the answers. I have applied this principle to coverage of descriptive material about the metals and nonmetals. The accompanying Metals Puzzle corresponds to material in Chapter 20 of "Principles
of Chemistry" by Davis, Gailey and Whitten. T h e Nonmetals Puzzle, which appears on page 1113, corresponds to material in Chapters 21 and 22. The puzzles were constructed with the aid of the Crossword Magic computer program (a product of L & S Computerware) using an Apple IIe computer. Students were given the first puzzle about mid-semester and were allowed a maximum of three weeks t o finish it. On turning in the first puzzle they were given the second oneto he completed by the first of May (about three weeks before the end of the semester so as not to load them with excessive work a t the very busy time a t the end of the semester). There are 20 words in the Metals Puzzle and 30 words in the Nonmetals Puzzle. Allowing two points for each correct word gives a total of 100 points (equivalent to one hour exam).
Metals ACROSS 2. The property of being able to act either as an acid or a base. 5. A metal used in jewelry and coins. 6. A metal that can exhibit amphoterie properties. 7. An ion that imparts a deep purple color to an aqueous solution. 9. A metal that is a liquid at room temperature. 12. A metal found in hemoglobin. 13. A metal that is used to galvanize steel. 15. A metal found in chlorophyll. 18. An element that can exhibit oxidation states from +2 to +7. 19. An alkali metal. 20. A metal whose ion is found in salt water. DOWN 1. This name is given to the process of electrolyzing aluminum oxide to aluminum. 3. The process of purifying a metal after smelting. 4. The elements filling the d subshell. 8. The process of reducing a metal oxide to a free metal. 10. A metal used to coat automobile humpers. 11. A group in the Periodic Table having relatively low ionization potentials. 14. Any element whose oxide forms a base when dissolved in water. 16. Alkaline earths. 17. An element, found free in nature, that is reddish yellow in color.
(Answer key on page 1117) Volume 62
Number 12
:
December 1985
1103
