VOLUME 33. NO. 10, OCTOBER, 1956
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ATOMIC MODELS FOR A BEGINNING COURSE IN COLLEGE CHEMISTRY VANCE H. DODSON University of Toledo, Toledo, Ohio
THREE-DIMENSIONAL models of the oxygen and sodium atom have been previously described in THIS JOURNAL.'. The atomic models used by the author and described herein for the introduction of atomic structure in a beginning course in college chemistry are three dimensional but much simpler in their construction (see the figure). The orbits are made of steel wire (approximately J/lrinch diameter) and are soldered to the frame work of the model. Each orbit of a given model is wrapped with a different colored plastic tape to make differentiation easier for the student during lecture demonstrations. The outermost orbit is 32 inches in diameter. The distances between the inner orbits vary and were chosen arbitrarily t o afford maximum visibility. Cork balls, two inches in diameter, which are painted a bright red, serve as electron^.^ These balls have been slotted so that they can be readily attached to or removed from the metal orbits. The nucleus of the model atom is a clear plastic ball, four inches in diameter, that has been cut through its middle. The lower half is fastened to the metal frame work. The upper half rests snugly on the lower stationary portion and can be easily raised or lowered when the nuclear particles are added. Cork balls, % inch in diameter and painted black, are used to represent protons. Balls of the same size but painted white are used to represent neutrons. Since the nuclear particles are visible, the simultaneous build up of the nucleus with the electronic rings becomes a very simple but effective demonstration.
' BROOKS,W. O., J. CHEM.EDUC.,24, 245 (1947).
' HALL, J.A,, J. CHEM.EDUC.,24,564 (1947).
'The cork balls used in the construction of the atomic models N. Second Street,
were purchased from Erno Products Co., 65
Philadelphia, Pennsylvania.
The models are also used to demonstrate atom to ion relationship, isotopic forms of a given element, electrovalent bond formation, and covalent bond formation. The latter is done using electrons (cork balls) that have been slotted on two sides so as to allow their attachment to orbits of more than one model a t a time. The models can be used successfully if the student is properly impressed with the fact that the Bohr model of the atom is one of the earliest to be presented and that, although it illustrates some of the important points of atomic structure, it is not entirely correct. The author wishes t o thank Mr. George B. Tann for his assistance in the construction of the atomic models.
