Periodic table color scheme

Benzenoid (chemical) isomers are, in a strict sense, the benzenoid systems compatible with a formula C H, = (n s). The cardinality of C HS, viz. C HS = n, s is the number of isomers pertaining to the particular formula. The generation of benzenoid isomers (aufbau) is treated and some fundamental principles are formulated in this connection. Several propositions are proved for special classes of benzenoids defined in relation to the place of their formulas in the Dias periodic table (for benzenoid hydrocarbons). Constant-isomer series for benzenoids are treated in particular. They are represented by certain C HS formulas for which n s = In Sjl = n2 52 =. .., where (nk sk) pertains to the k times circumscribed C HS isomers. General formulations for the constant-isomer series are reported in two schemes referred to as the Harary-Harborth picture and the Balaban picture. It is demonstrated how the cardinality n s for a constant-isomer series can be split into two parts, and explicit mathematical formulas are given for one of these parts. Computational results are reported for many benzenoid isomers, especially for the constant-isomer series, both collected from literature and original supplements. Most of the new results account for the classifications according to the symmetry groups of the benzenoids and their A values (color excess). 

Figure 16.5 Computed (TDDFT/PBE38) Cg dispersion coefficients (in Bohr°) for the whole periodic table (up to Pu), which are used in the DFT-D3 method- For each element the free atom value (lower value, light colored circle) and the coefficient (upper value, darker color) for the atom in a saturated chemical environment (with the highest coordination number according to the DFT-D3 scheme, e.g., four for carbon and three...

Color-coded periodic tables emphasize the classification of the elements as metals (blue), nonmetals (tan), and metalloids (green). Please study the periodic table inside the front cover carefully so that you recognize this color scheme. 

FIGURE 3 The modern long form of the periodic table. The color (shading) Scheme is discussed in Sections VI through IX. 

Through the color scheme of the periodic table on the inside front cover, we see that the majority of the elements are metals (tan) and that nonmetals (blue) are confined to the right side of the table. The noble gases (pink) are treated as a special group of nonmetals. Metals and nonmetals are often separated by a stairstep diagonal line, and several elements near this line are often called metalloids (green). Metalloids are elements that look like metals and in some ways behave like metals but also have some nonmetallic properties. 

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