e d l t e d by
learning activitiw Flow Chart for Naming Inorganic Compounds David Robson
TOM
TIPTON
UnlversQ of Nebraska Lmcoln NE 68508
Preliminary Skills for Naming Compounds Flow Chart There are seven preliminary skills which the student must master before using the flow chart The specific limits of each skill, which are given in parentheses. ma" be chanoed to suit the teacher.
Towson Senior High School Towson. MD 21204 (Baltimore County School System)
High school textbooks typically present inorganic nomenclature as a set of rules which the students are to memorize before they can begin to apply them. Thus, the teacher must assume the task of explaining each rule and providing some drill a t the blackboard which consumes valuable classroom time in mastering what is fundamentally a simple, mechanical task. The flow chart approach presented below has advantages for both the student and the teacher. I t allows the student to begin naming compounds immediately-he can literally name c o m ~ o u n d before s he knows what thev are and how to do it. I t is not necessary to memorize a set of rules, for they are embodied in the structure of the chart. The students use this pedagogical tool until nomenclature becomes automatic. This flow chart has been used successfully a t several high schools in the Baltimore County System. The chart is used at Towson H i ~ School h in the following manner. First, the preare reviewed in classrom instruction. (See Table.) Second. homework drills are assigned on ten successive days. Each drill assienment contains the formulas of 20 comoounds to be
62) 3. Memorize the names. formulas. and oxidation numbers of selected polyatomic ions (e.g., sulfate, nitrate, carbonate, acetate. phosphate, chlorate, hydroxide, ammonium. cyanide, iodate). Note that a compound which contains a .~olvatomic ion must have more than two elements. . 2 Vellur ?e in? C ; C S lor CC! . ng Irk, r h n l r . on.1 or 13. on n.mm : c l h! ,.IN P O , 310m c on3 nn cn 3 iler rr I! I : i m a ' r 01 o~,r,enxomc L~i.rnl.I : i me 5 l . m ~ n5i memo! r m :!#LC (: 01 5 n m e a crl at ;te 11%: .tn 1l.r .r the name C I O as hypochlorite. etc.) 5. Using the periodic table, determine the most probable oxidation number of the non-transition elements. (Sodium is itbecause it is in group IA; oxygen is 2 because it is in group VIA, e t c ) 6. Memorize a list of selected common metals which have more than one Oxidation number. (e.g., iron, nickel, copper, tin, mercury. lead) 7. Learn to determine the oxidation number of the elements listed in 6, above, from the formula of the compound. (Example: in the compound Fe,Osthe oxidation number of iron must be 3+ because oxygen is 2Tand the algebraic sum of the oxidation numbers must be zero.) ~~~
~
stead, at the beginning of the class period, the instructor merelv checks to see that each student has comnleted the assignment. Answers are then presented on the overhead projector, and each student corrects his own paper. This re-
Naming Compounds Flow Chart begin with H'!
I Does the aeld coniain a polyalomlc lo"? (More than two elements) Yes
pa1,~rtornic ion? (hlnro than two elemellLs., 1 a
No
Does the pnlyalomie ion end in o i s or rlt?
replacing the iie ending with our. Add the woid 10".
h y d r o . then the name of the second element ,&ill>ie
ending. Add the word a c i d .
1
1 mono
di 3 tii
il tetra 5 pentr 6 hem
Volume
60
Number 2
February
1983
131
quires only five minutes of class time, freeing the remainder of the period for learning more complex concepts. Finally, the students take a quiz on naming compounds, during which they are not Dermitted to use the flow chart. After usine the chart to workiome 200 examples for homework, the stu~dentsfind it easv to make the transition to namine comnounds without this aid. With ample practice, they are ablk to absorb the structure of the chart without explicitly memorizing it.
MATERIALS Lead shot, Petri dishes, and platform balance. PROCEDURE 1) Students working in pairs are asked to count 6.02 X lo2 atoms of Parkwaydium and place them in a Petri dish. 21 Students are told that this auantitv has s ~ e c i asienifil
.. -.-.... -J
Determination of the Mass of an Imaginary Atom Mike Rabourn Parkway High School 1701 Curtis Loop Bossier City. LA 71112
PURPOSE
ered).
132
Journal of Chemical Education
3) Students are then required to weigh these atoms on a platform balance, The concept of gram atomic weight is introduced and related to the mole. 4) Based upon their experimental data, the students are finally asked to determine the average mass of a single atom of their imaginary element. (It is often useful to let a student attempt to weigh a single lead shot so that he might see the necessity of relying upon calculations when working with particles too small to be individually weighed.)
