edited by
J. DUDLEY HERRON
hqcb
Purdue University West Lafayene, Indiana 47907
A Hyperspace P e r i o d i c Table: An O r b i t a l - F i l l i n g Exercise for High School Students
Energy
Sublevels
Orbitals
Edward L. Waterman Rocky Mountain High School 1300 West Swallow Road Fort Collins, CO 80526 One of the nrohlems facine" the hieh school chemistrv " teacher is to teach the basic concepts of modern atomic theory without using complex mathematical ideas about wave functions, quantum numbers, and orbitals. Teaching only the Bohr theory of the atom a t the high school.level is unacceptable hecsuse too often students enter college chemistry with an idea of the atom which is more than fifty years out of date, and which fails to answer many pertinent questions about atoms. Some excellent non-mathematical discussions of the nature of wave mechanics and the modern atomic theory have been puhlished ( I , 2). Additionally, recent literature has documented several oractical annroaches to the teachine of .. concepts derived from the wave-mechanical model which are appropriate for the high school level (3-9). I wish to report an exercise suitable for high school students which helps to relate the Aufbau process and electron confiauration to the periodic tahle. ~ u r t h k rit, helps to illustrate ananswer to the common question, "Why is the periodic tahle shaped the way it is?"' After the class is introduced to general non-mathematical aspects of the wave-mechanical model of the atom, the Aufbau process, electron configuration, and periodic properties, the following exercise is carried out in class.
Figure 1. Energy level diagram for constructing hyperspace periodic table.
v
Preliminary Information Yuu are an astronaut who lands on an imaginary planet in hyperspare where only 40 elements exist. After studying some spectroscopic data and doing some wave-mechanical calculations you determine that the electrons in the atoms of the hyperspace planet occupy 5 principal energy levels labeled 1, 2.3.4 and 5. Level 1 can contain 2 electrons, level 2 can contain 6 electrons, and levels 3, 4, and 5 can contain 12 electrons each. Electrons in each principleenergy level are distrihutedamangoneor moresublevels which arelabeledo, b,and L.. Sublevel a contains 1 orbital. sublevel b contains a set of 2 orbitals. ijnd w I ~ . r \ v . ~.~,nti)in. a i t i (11 :
