The Chemical Language

As we already saw in the previous section, chemistry, like any discipline of science, has its own system of naming material species. Initially, students may be intimidated by the myriad of names that do not mean much to them. But like in any new language, the feeling improves tremendously after acquiring a basic vocabulary. For our purposes, it is advisable to know the names of the first 18 elements/atoms in the periodic table. There will be no special punishment for those who would know more names The 18 atom names are given in Appendix 2.1 at the end of the chapter. If 

SCHEME 2.1 Some molecules and the conventional way of writing their atomic composition are shown along with a caricature of J. J. Berzelius, the inventor of this language. (The caricature is reproduced with kind permission from its artist, the historian W. B. Jensen) 

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The theory of band structures belongs to the world of solid state physicists, who like to think in terms of collective properties, band dispersions, Brillouin zones and reciprocal space [9,10]. This is not the favorite language of a chemist, who prefers to think in terms of molecular orbitals and bonds. Hoffmann gives an excellent and highly instructive comparison of the physical and chemical pictures of bonding [6], In this appendix we try to use as much as possible the chemical language of molecular orbitals. Before talking about metals we recall a few concepts from molecular orbital theory. 

Chemists working on the same problems could only know they were studying the same substances if they spoke the same language. The chemical language, like chemical instruments, defined the discipline.46 The instruments and the nomenclature were illustrated in elaborate diagrams and "tableaus." Lavoisier s "Tableau des substances simples" is one of the most famous. (See fig. 1.) Here he organizes thirty-three simple substances into four categories ... 

Berzelius (1844) introduced the term allotropy as the phenomenon of polymorphism in elements. There has been some debate about the necessity of a special term to designate the polymorphism of elements, as opposed to compounds (Sharma 1987 Reinke et al. 1993), but the term is still introduced in first year chemistry texts, so it has become part of the chemical language. Sharma (1987) has given some examples... 

Figure 6.38 shows schematically how the two-dimensional structure is turned into valuable information. The two-dimensional structure is the common representation of a molecule in the chemical language as it is obtained from structure editor software. This representation does not include explicit information about the spatial arrangement of atoms. Several atoms in this molecule can appear in different spatial orientations leading to different enantiomers. 

Names and formulas of compounds form the vocabulary of the chemical language. In this discussion, you ll learn the names and formulas of ionic and simple covalent compounds and how to calculate the mass of a unit of a compound from its formula. 

When we come to cosmetics, of course, the chemical language is frightening. In Australia at least, the buying public does seem well aware that the scientific jargon on cosmetics is designed to impress and, broadly, they are not taken in by this strategy. 

An understanding of the chemical language that controls the social and feeding behavior of an Individual species would be useful in the care and breeding of that species. However, research on the assignment of structure-activity relationships in mammalian behavior is only in its Infancy. 

As noted earlier, chemistry is a language. Success in the study of chemistry depends upon how well chemical language is learned. This chapter presents the last of the most basic parts of the chemical language. When it has b n learned, the reader will have the essential tools needed to speak and write chemistry and to apply it in environmental and other areas. 

A common error in speaking the chemical language is to confuse acidic (pronounced uh-sid-ik) with acetic Qnjonounced uh-seat-ik). What is the correct meaning of each of these terms What is the difference between ammonia and ammonium ... 

Thus, while I thought myself employed in forming a Nomenclature, and while I proposed to myself nothing more than to improve the chemical language, my work transformed itself by degrees, without my being able to prevent it, into a treatise upon the Elements of Chemistry . 

Brock WH, Jensen KA, J0rgensen CK, Kauffman GB (1982) Searching the Literature To Learn How the Term Ligand Became a Part of the Chemical Language. J Chem Inf Comput Sci 22 125-129... 

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