reviews MacMendeleev: A Program for Exploring t h e Periodic Table Jon Clardy, Cornell Univemity,Trinity Software, P.O. Box 960, Campton, NH 03223 Hardware Requirements:
Components: Level and Subject:
Apple Macintosh 1 Megabyte RAM 1 800K Disk Drive [Optional] Hard drive [Optional] Printer Manual and Disk College, Periodic Table
Summary R a t i n g s Ease of Use Subject Matter Content Pedagogic Value Student Reaction
Good Good Average Average
This program is essentially a data base for pmperties of the elements. Praoerties are Name, Symbol, Abundance (earth, humnn,sra,sun,un~versr,.Aromicnumher,themmalConductivit)., Deniity 25 .C,, year of D~scuveq,Electron f l h t y , Eleclronrgntwit), Encrg).ofianlzatrun < + I , +2, + 3 , 4 ,Enthalpy atomimtion, bonding, fusion, vaporization), Heat capacity, number of Isotopes, ahundances and mass numbers of three mast common Isotopes, atomic Mass, exact nuclidic Mass, atomic Polarizability, stable Radioisotopes, Radius (atomic, covalent,van der Wad's, ionic far states +1, +2, +3, -1, -21, electrical Resistivity, Temperatures (bailing point, critical paint, DeBye,melting point, superconducting), atomic Volume, and X-ray emissions (K,L, M). The periodic table may be displayed with several different types of column headings; Old IUPAC Groups, New IUPAC Groups, CAS Groups, and No Groups. These properties may be displayed individually as 3-D plots rising out of the periodic table far all elements or any seleded subset. Prooerties mav be scaled in absolute values or lomrithmically,anamny h r - ~ n v e r t r dwithsmallrrvnlurs rlsmghlgher than larger values. E l e m m t ~may h~ ielected directly from the peraldic tahle, ur by selecting a11 element, which fall within a sprclfied range of values for particular property (or a seleded pair of properties). A contiguous group of elements may he selected directly from the periodic table by dragging the mouse over the group, while scattered elements may he selected by clicking the mouse while holding dawn the shift key. There is a capability for
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Reviewed
inverting the selection process, to select all elements except the designated group. Two properties may he chosen and displayed as an XY plot for a selected group of elements, again either as absolute values or their laearithms. Unfortunatelv. there is no orovision for re-scalina of th&e plots to display the brigin or a crossing point for two seG of data. Properties may also be displayed in tabular form, as a seleded group of properties for a selected group of elements, sorting on one chosen property. There is no provision for editing the table by re-sortine on a different orooertv or bv rearraneine the columns. While t h ~ r~ o l n t ,rboth . 3-D'ani Xf~ mavbeorinteZdSectlvar - . ~ ~ ~ ,saved ~n a file, tableicannor he printed dlreetly, hut muat hesavedas an ASCII f lc to hr read into a word p n c r s w r pruLmm f i r pnnttng. Since numbers are presented in mixed format (varying digits after the decimal, some in exponential notation) this makes the preparation of puhlication-quality tables very awkward. The program a,na run on hoth a Marmtosh Plus and a Mxlntuch llri lhr first pmblem encuunterrd was irc attempting to boot the pro~amunderMCLT1F'ISI)EHl'hrprohlrmwospinpointedu~ith i quick telephone call, and the program then ran normally under FINDER. Very little documentation is required to operate the program, which is completely menu driven, and the accompanying manual is very clearly written. Relatively inexperienced students had no difficulty with the program. However, the program locked up in attempting to generate an XY plot of electrical resistivity versus atomic number for elements in the third row. The lockup is only evidenced by nanaction with the timer (indicating a delay1 displayed on the screen. The program would not rehaat from the RESET switch, requiring ejection qf the disk and rebooting off of the hard disk hefore reinserting the disk. The immediate difficulty here seems to be in the extreme range of values of the electrical resistivity. Generation ofa similar plot for the second row elements showed some flaws in the ~ ~ a p h iwr tsh some blnck splorrhci on the screen. L'sing the log Y option under PREFERENCES pruducrd nn unflnwed d o t for both data set* H o w \ e r , with this graph displayed under log Y for the third row elements, removal of the log Y option resulted in a lock up. The data base appears to he correct and comprehensive, and references for the source of data are readily accessed within the program. The program also includes afaeility to modify and extend the data base. This program is an excellent resource for anyone workingwith propertiesofelements. Itslsa may heused to produce teachine aids far lectures a t several educational levels from hieh school to maduste onuminl with arbitrary ronstnnts is used and nll theconstants arc cvnlunted along wirh thrperrcnt confidencethat each constant is significantly different from zero. The program can then be used tocalculate thepredietedresultfromeach experiment using this model, and then calculates residuals. The software can then~alsomake plots of the anticipated results for various comhinations of the inhependent variables using this model. An advanced eraduate student used this software to examine somedata involwng three i n d c p m d ~ nvariablri t where thecorrect equation connecting the vnnahles to the expenmental results was k n w n to be very dimerent frurn n second-order polynomial. The second-order polynomial and another arbitrary equation involving the square roots of two of the variables and the logarithm of the third were presented to the program with undetermined coefficients. As might he expected, large residuals were obtained far some of the data. Also as expected, the program gave very small residuals when the correct equation was used. Unfortunately, there is no way in which this software can he used to give guidance to the user about the correct equation to he used except by careful examination of the results, especially the residuals, using equations whose form is alreadv known. This software nackaw ,. oroha, hly ~ v c hcst s results H hen the drpendencr of the experimcntnl results on the mdrpcndrnt varrablcs is rrlnrively simplc T h i suftwsrc package appcaarz to be extremely specialized and P U T P O S ~ S . It could roneewahly be used not meant for p~dago~
