untitled Derivatio chemical Nazmul Isla Department of Ba *Corresponding a fax: +91.35222711 ARTICLE INFO Received: 05 May Received in revis Accepted: 17 Feb Online: 31 Decem KEYWORDS Electronegativity Orbital exponent Mulliken electron Gordy electroneg Chemical reactivi Convergence of G 1. Introductio The conc chemical thou established th every branch physics, engin Although t with the work definition and by Pauling electronegativ attract electro definition and theoretical co electron attra extensively us the heteronuc atoms. Thus polarity of th nuclear molec principle was Despite its [6,12‐16] belie and there is n benchmark f electronegativ 1.1. The Gordy The conce work of Von L H‐like ions the the nucleus: in most shell (n on of Gord l reactivit am asic Science and Hu uthor at: Departme 101. E‐mail addres ORMATION y 2010 ed form: 17 Febru ruary 2011 mber 2011 y negativity scale gativity scale ity descriptors Gordy’s and Mullike on ept of electro ught for nearly at the electrone (both theoretic eering and biol the idea of atom k of Jöns Jacob d meaning of a [2,3] in 1 vity as “the po ons toward itsel d the scale o ncepts were d acting power, a sed to study the clear molecule the atomic e he molecule. T cule formation, proposed by Sa s manifold usef eve that electro no experimenta for electroneg vity is very diffic y’s electronega ept of screenin Laue [18] and M e electrons exp n a multi‐electr nearest the nu Eu ISSN 2153‐ Europ J dy’s scale ty manities, Techno G ent of Basic Science ss: nazmul.islam786 ary 2011 en’s scale onegativity ha about 140 yea egativity is an in cal and experim logy. mic electronega b Berzelius [1] atomic electron 1932. Pauling wer of an atom lf”. After the an f atomic elect eveloped. Bein atomic electron e amount of cha e formation fr electronegativit o explain the the electroneg anderson [4]. fulness [3‐11], a onegativity is an al as well as q ativity. It is cult to define [1 ativity ansatz g begins in 19 Moseley [19]. In perience a full a ron atom, the e cleus) will exp uropean Journal Europe 2249 (Print) / IS DOI:10.515 pean Jo Journal home e and com Global‐Balurghat, B e and Humanities, T 6@gmail.com (N. Is ABSTRACT A new atomic definitions of G to satisfy all t electronegativit Comparative s electronegativit d been a par ars. Now a day ndispensable to mental) of chem ativity was init , the first scie negativity was g g defined at m in a molecu nnouncement o tronegativity, m ng a measure o negativity has arge transfer du rom its constit ty determines process of he gativity equaliz a group of scien n empirical qua uantum mecha also opined 15‐17]. 912 with the ea n case of H‐ato attractive force electron in the i perience the w of Chemistry 2 ( ean Journal of Ch SSN 2153‐2257 55/eurjchem.2.4 ournal o epage: www.e mputation Balurghat, 733101, Techno Global‐Balu slam). electronegativit Gordy and Mullik the sine qua n ty data is used studies reveal ty is a successful rt of , it is ool in mistry, tiated ntific given tomic ule to of the many of the been uring tuent s the etero‐ ation ntists antity anical that arlier om or from inner whole nucl the elect nucl shie S to d elect T repr Zeff = whe T char  = Z T atom pote to at χ = e G scale equa cova elect χ = a (4) (2011) 448‐4 hemistry (Online)  2011 .448‐454.94 of Chem eurjchem.com of some u India urghat, Balurghat, ty scale is propo ken. The new co non of a reaso d to compute so that the new l venture. lear charge of Z electron will trons. This rep leus on the ele lding of the elec Slater [18] coin escribe the net tron in a multi e Thus, Zeff = Nu resenting the av = Z‐S ere S is the scree The orbital exp rge (Zeff) and th Zeff/n* The concept of mic electronega ential felt by the tom at the singl e (Zeff/r) Ghosh and Cha e by suggestin al but proport alent radius b tronegativity an a(Zeff/r/)+b 454 1 EURJCHEM mistry m useful des 733101, India. Tel. osed by using t omputed atomic onable scale of ome useful desc approach to Z units; if it is i feel repulsion pulsion reduce ectron of inter ctron from the ned the term “e t positive charg electronic atom uclear charge ‐ verage electron ening constant ponent,  is the e effective prin screening is us ativity (χ) of a e valence electr le bond covalen kraborty [12] m ng that the ato tional to Zeff/r by the absolu nsatz: scriptors .: +91.9432878737; the essence of e c electronegativi atomic electro criptors of chem derive the Go in the outer pa n from the re s the attractio rest, and is the nucleus. effective nuclea ge which is exp m. point charge repulsion. i.e., or shielding co e ratio of the ef cipal quantum sed by Gordy [2 an atom as th rons at a radial nt radius (r). modified the el omic electrone and also they ute radius in of 7; electronegativity ity data is found onegativity. The mical reactivity ordy’s scale of art of the atom, emaining inner on force of the e screening or ar charge” (Zeff) erienced by an at the nucleus (1) nstant. ffective nuclear number (n*) (2) 20] to define the he electrostatic distance equal (3) ectronegativity egativity is not y replaced the n the Gordy’s (4) y d e . f , r e r ) n s r e c l y t e s Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 449 where r/ is the most probable radius of the atom and ‘a’ and ‘b’ are constants. They also proposed the value of the constants for each period. Although the new look (Equation 4) of Gordy’s scale satisfies the entire criterion of a reasonable scale of atomic electronegativity and it can successfully explain several chemical facts, we noticed that the atomic electronegativity values of the members of the halogen family and H atom computed by Ghosh and Chakraborty (GC) [12] follow the order: χF > χH > χCl > χBr > χI . Thus, the use of the GC atomic electronegativity values [12] for the computation of the dipole charge and dipole moment and also the atomic polar tensor of the hydrogen halides is not efficacious. Furthermore, the modified atomic electronegativity value for the alkali metals and alkaline earth metals are in the reverse order than expected. So, the modification of the Gordy’s [20] scale is not complete yet and it demands more study. In a recent work, we [21a,b] have found that the Gordy’s electronegativity ansatz can be derived from the Mulliken’s definition of electronegativity [22] as well as the density functional definition of electronegativity [23]. In the instant work, to derive the Gordy’s electronegativity scale, we proceed as follows‐ Classically, the energy E(N) of charging a conducting sphere of radius r with charge q is given by [24‐26] E(N)=q2/2r (In C.G.S unit) (5) In Equation 5, E(N) is in ergs, q is in electrostatic unit and r is in cm. Now, for an atom, the change in energy associated with the increase of q, on removal of an electron (of charge e), would be the ionization energy, I. Similarly, the energy evolved on addition of an electron with q would be the electron affinity, A. Hence, I=E(N+1)‐E(N)={(q+e)2/2r}‐q2/2r (6) and, A = E(N)‐E(N‐1)=[(q2/2r)‐{(q‐e)2/2r}] (7) Since, χM = ½ (I + A) (8) χM = ½ [ {{(q+e)2/(2r) }‐(q2/2r)}+{ (q2/2r)‐{(q‐e)2/2r}] (9) or, χM = qe/r (10) where e is the electronic charge in e.s.u. Now, q= Zeff e (11) We can write using the Equations 10 and 11 χM = Zeff e2/r (12) In atomic unit Equation 12 looks like χM = Zeff/r = χG (13) 2. Method of computation In a recent work [21b], we have evaluated the orbital exponent values of 118 elements of the periodic table following the rules for light and heaviest elements laid down by Reed [27] with some modifications as under‐ We considered Reed’s suggestion for s, p and d and extended Reed’s rule for f. Electron in the 5f, 6p and higher we have used the contribution of 4f as 1. In the same shell f electrons shield each other by a factor 0.3228. Ghosh et al. [28] defined the absolute or most probable radius of atom as: r=n*/ ξ (in au) (14) If we replace the Zeff and r from Equation 13 using the Zeff (Equation 2) and r (Equation 14), the atomic electronegativity definition of Gordy looks like‐ χ = ξ2 (in au) (15) At this outset, following Ghosh and Chakraborty’s [12] suggestion, we proposed that the atomic electronegativity is not exactly equal but proportional to the orbital exponent of atoms. Thus, χ  ξ2 (16) The utility of the Equation 16 is that only one atomic parameter, the orbital exponent (ξ) is sufficient to define and also to compute the electronegativity of the atoms. But as there is a proportionality relationship between the two atomic parameter‐χ and ξ, to compute the electronegativity of the atoms some constants are required. The linear relation, χ=m ξ2+c may be adopted for that purpose. Or we may use a very simple relation χ = m ξ2. In each case, to evaluate the proportionality constant (s), we have to compare the ξ2 with some set of reference data. In the present work, we consider the simple equation (17) to compute the electronegativity data of atoms. χ = m ξ2 (in au) (17) The constant, m is found to be dependent on the principal quantum number. This implies that it is constant throughout a period. The values of m for each period were computed by comparing the ξ2 values with the Ghosh Chakraborty (GC) atomic electronegativity values (in au) [12]. To evaluate the orbital exponent, we have used the values of n* which was evaluated by Slater [18] for n=1 to n=6 and for n=7 we have used the value of n*=4.3 computed by Ghosh and Biswas [25]. Using the newly computed orbital exponents and the m parameters, the atomic electronegativity of 118 elements of the periodic table was computed in this work (Table 1). Although there is a view [29] that electronegativity is a quantum mechanical observable, we [6,12‐14,30] strongly do believe that electronegativity is not a physical observable. Therefore, to perform the validity test of the newly computed electronegativity data, we have computed four very important and useful descriptors of chemical reactivity using the electronegativity values computed by us. 3. Computation of some useful descriptors of chemical reactivity Pauling [2] evaluated the bond length from the atomic electronegativity, derived from the heats of formation or essentially bond energies. The atomic electronegativity differences between two atoms reflect the strength of the bond to give a quantitative correlation between atomic electro‐ negativity and bond polarity. Using a simple bond charge model (SBC) [31], Ray et al. [10] derived the heteropolar bond length, RAB, in terms of the atomic electronegativites, χA and χB , and covalent radii, rA = 1/2RAA and 1/2RBB, of atoms A and B as follows‐ RAB = (rA+rB)‐{(rArB(χ1/2A ‐ χ1/2B)2}/(χA rA + χB rB) (18) 450 Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 Table 1. Computed orbital exponent and electronegativity of the present work (χCal) along with the electronegativity data computed by Ghosh and Chakraborty (χGC). Atom ξ χCal (eV) χGC(eV) Atom ξ χCal (eV) χGC(eV) Atom ξ χCal (eV) χGC(eV) H 1 6.271905 7.17841 Nb 0.81038 1.268716 3.5022 Tl 0.92557 0.710963 4.66107 He 1.6772 17.64287 12.0486 Mo 0.8318 1.336672 3.55471 Pb 1.08681 0.980247 4.73998 Li 0.6634 0.743654 3.22229 Tc 0.85323 1.406433 3.60968 Bi 1.24805 1.292684 4.82978 Be 1.002 1.696507 3.79419 Ru 0.87465 1.477936 3.66682 Po 1.40929 1.648273 4.92773 B 1.3406 3.036817 4.59509 Rh 0.89608 1.551245 3.72614 At 1.56945 2.0442 5.03385 C 1.6792 4.764584 5.62461 Pd 0.9175 1.626294 3.7879 Rn 1.73176 2.488879 5.15085 N 2.0178 6.879809 6.8834 Ag 0.93892 1.703115 3.85212 Fr 0.53656 0.238927 2.72644 O 2.3564 9.382491 8.37031 Cd 0.96035 1.781747 3.91878 Ra 0.69405 0.268698 2.8244 F 2.695 12.27263 10.0854 In 1.12965 2.465328 4.2336 Ac 0.71398 0.284351 2.85161 Ne 3.0336 15.55023 12.0317 Sn 1.29895 3.259656 4.5925 Th 0.73391 0.300447 2.87882 Na 0.76907 0.898038 2.5378 Sb 1.46825 4.164731 4.99521 Pa 1.02895 0.590569 3.13731 Mg 0.9948 1.502569 2.97449 Te 1.63755 5.180552 5.44173 U 1.18644 0.785189 3.3169 Al 1.22053 2.261828 3.5237 I 1.80685 6.30712 5.93178 Np 1.34393 1.007478 3.5237 Si 1.44627 3.175861 4.1852 Xe 1.97615 7.544435 6.46618 Pu 1.63898 1.498407 3.95089 P 1.672 4.244586 4.9591 Cs 0.54933 0.250435 4.43251 Am 1.79647 1.800207 4.26381 S 1.89773 5.468039 5.8458 Ba 0.67714 0.380527 4.46979 Cm 1.95395 2.129655 4.29374 Cl 2.12347 6.846285 6.84459 La 0.73098 0.443445 4.51686 Bk 1.97388 2.173321 4.85699 Ar 2.3492 8.379203 7.9552 Ce 1.03305 0.885668 4.57346 Cf 2.26893 2.871604 5.20799 K 0.62357 0.687721 2.78821 Pr 1.19429 1.183717 4.63958 Es 2.42642 3.284085 5.58621 Ca 0.80659 1.150661 3.0128 Nd 1.35552 1.524896 4.71522 Fm 2.58391 3.724236 5.98892 Sc 0.82976 1.217718 3.0728 Pm 1.51676 1.909247 4.80066 Mv 2.7414 4.192057 6.41884 Ti 0.85292 1.286644 3.1359 Sm 1.678 2.33675 4.89562 No 2.89888 4.687517 6.87325 V 0.87608 1.357467 3.2021 Eu 1.83924 2.807406 5.00011 Lr 2.91881 4.752193 6.98209 Cr 0.89924 1.430188 3.2713 Gd 2.00024 3.320417 5.11412 Rf 2.93874 4.817312 ‐ Mn 0.92241 1.504839 3.3437 Tb 2.16171 3.878138 5.23793 Db 2.95867 4.882873 ‐ Fe 0.94557 1.581355 3.41899 Dy 2.32295 4.478248 5.37153 Sg 2.9786 4.948878 ‐ Co 0.96873 1.659768 3.4976 Ho 2.48419 5.12151 5.51438 Bh 2.99853 5.015326 ‐ Ni 0.99189 1.740079 3.5791 Er 2.64543 5.807924 5.66703 Hs 3.01847 5.082251 ‐ Cu 1.01505 1.822287 3.66369 Tm 2.80667 6.537491 5.8292 Mt 3.0384 5.149586 ‐ Zn 1.03822 1.906429 3.7515 Yb 2.9679 7.31016 6.00089 Uun 3.05833 5.217363 ‐ Ga 1.22124 2.637813 4.16721 Lu 2.98831 7.411049 6.18238 Uuu 3.07826 5.285584 ‐ Ge 1.40427 3.487732 4.64061 Hf 3.00871 7.512579 6.37041 Uub 3.09819 5.354248 ‐ As 1.5873 4.456151 5.172 Ta 3.02912 7.61485 6.57394 Uut 3.10888 5.391261 ‐ Se 1.77032 5.543007 5.76101 W 3.04952 7.717761 6.784 Uuq 3.26637 5.951318 ‐ Br 1.95335 6.748419 6.4079 Re 3.06993 7.821415 7.00413 Uup 3.42386 6.539046 ‐ Kr 2.13638 8.07233 7.11269 Os 3.09033 7.925709 7.23351 Uuh 3.58135 7.154445 ‐ Rb 0.5768 0.642743 3.1886 Ir 3.11074 8.030744 7.43459 Uus 3.73884 7.797514 ‐ Sr 0.7461 1.075427 3.3588 Pt 3.13114 8.13642 7.72084 Uuo 3.89633 8.468254 ‐ Y 0.75178 1.091864 3.4043 Au 3.15155 8.242838 7.97906 Zr 0.78895 1.202502 3.45211 Hg 3.17195 8.349896 8.24681 To predict the polarity of a chemical bond, Pauling [2] proceeded to derive an algorithm for the dipole charge, and plotted these percentages against their atomic electronegativity differences to give an equation to calculate the ionic character of a bond (dipole charge) using‐ q = 1‐ exp {‐(χB ‐ χA)2/4} (19) where χB and χA are the atomic electronegativities of atoms B and A respectively. A good number of empirical equations were suggested by various workers to evaluate the dipole charge invoking atomic electronegativities of the bonded atoms from various scales. We have invoked three other equations, stated below, for the study of the dipole charge of some heteronuclear diatomics. Nethercot [32] proposed two formulae to calculate the dipole moment charges as: Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 451 q = 1‐ exp(‐3(χB ‐ χA)2/2χAM2) (20) and, q = 1‐ exp(‐(χB ‐ χA)3/2/χGM 3/2) (21) where χAM and χGM are the arithmetic mean (AM) and the geometric mean (GM) of the two atomic electronegativities. Barbe [33] proposed another simple equation to calculate the dipole moment charges as follows‐ q = (χB ‐ χA)/χB (22) Given, χB > χA. Dipole moments μd are caused by two opposite charges of magnitude q in Coulombs separated by distance r in meters. μd = q × r (23) The following form defines the molecular dipole moment μd = q × RAB (24) Here, RAB is the internuclear distance. In Debye, μd = 4.8 q × RAB (25) where RAB must be expressed in Å unit. Kim [11] extended the SBC model [31] to evaluate the atomic polar tensor. The atomic electronegativity and electronegativity equalization can be used to determine the atomic polar tensor for a diatomic molecule. Kim [11] proposed the algorithm for evaluating the dipole charge as follows: q={ r1r2/CRAB}(χB ‐ χA) (26) The centroid of positive charge, r, relative to the point defining the centroid of negative charge was given by Kim [11] as r = {r2ZB ‐ r1ZA ‐ (r1 + r2) q}/(ZA + ZB) (27) Kim 14 defined the dipole moment, µ, as µ = (ZA + ZB)r = ‐ (r1 + r2) q + (r1ZB ‐ r2ZA) = ‐ RAB q + (r2ZB ‐ r1ZA) = ‐ 1/C [(rArB χA χB) / (rA χA + rB χB)2][R2AB (χB ‐ χA)] (28) For an AB type diatomic molecule, where the A atom is located at the origin and the B atom is in a positive Cartesian direction and χB < χA the atomic polar tensors (Px’s) for atoms A and B was given by Kim [11] as PxB = ‐ PxA = (∂µ/∂R)e (29) where (∂µ/∂R)e is the dipole moment derivative at geometric equilibrium. Differentiation of the Equation 28 with respect to R gives the atomic polar tensor of B atom‐ PxB = (∂µ/∂R)e = ‐ (χB ‐ χA). 2RABrArBχA χB /6.9696 (rAχA+rB χA)2 (30) The computed orbital exponent, the atomic electro‐ negativity values and the atomic electronegativity values of Ghosh and Chakrabarty [12] are presented in Table 1. A comparative study of the computed atomic electronegativity data of the present work with Ghosh and Chakrabarty [10] computed atomic electronegativity data and is performed in Figure 1. The computed m parameters for each period are presented in the Table 2. Figure 1. Comparative study of the electronegativity of the present work vis‐à‐vis the Ghosh and Chakraborty’s electronegativity data. Table 2. Computed m parameters for each period along with effective principal quantum numbers Period Effective principal quantum number (n*) m values 1st 1 0.2305 2nd 2 0.06213 3rd 3 0.05579 4th 3.7 0.065 5th 4 0.071 6th 4.2 0.0305 7th 4.3 0.0205 In Figure 2, the variation of the computed electronegativity data along the groups 13‐17 is tested. Figure 3 shows the verification of silicon rule. In Figure 4, the atomic electronegativities of the members of the chalcogen family are presented. In Figure 5, the atomic electronegativity values of the inert gas elements are presented. Figure 2. Variation of electronegativity along the groups 13‐17. A comparative study of the computed atomic electronegativity of the H atom and the Halogen family with the electronegativity data of those atom computed by Ghosh and Chakraborty [12], Pearson [35], and Robles and Bartolotti [36] are presented in Figure 6. The internuclear bond distances of some heteronuclear diatomic molecules computed through the Ray et al formula [10] and using the newly computed atomic electronegativity values along with their spectroscopic counter parts [34] are compared in Figure 7. The dipole charges of a series of diatomic heteronuclear molecules, computed through the Nethercot arithmetic average formula [29], the Nethercot geometric average formula [29], the Pauling formula [2] and the Barbe formula [30] and using the new atomic electronegativities, and are compared in Figure 8. 452 Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 Figure 3. Verification of silicon rule. Figure 4. Electronegativity of Chalcogens. Figure 5. Electronegativity of the inert gas elements. The dipole moments of some heteronuclear diatomic molecules were computed using the newly computed dipole charges and internuclear distances of the diatomic molecules. The computed dipole moments (in Debye) and experimental results are compared in Figure 9. We have computed atomic polar tensor (APT) of halogen atoms in hydrogen halide molecules invoking Kim’s formula [11] and using the atomic electronegativity values computed by us. We have also computed atomic polar tensor of the halogen atoms in hydrogen halides using Ghosh and Chakraborty [12] atomic electronegativity value. To perform the validity test, two sets of APT values along with their experimental counterparts [11] are compared in Figure 10. Figure 6. Comparative study of the electronegativity data of H atom along with Halogen family of the present calculation vis‐à‐vis the data computed by Ghosh and Chakraborty, Pearson, and Robles and Bartolotti. Figure 7. The evaluated inter nuclear distance vis‐à‐vis the spectroscopic inter nuclear distance of a series of molecules. Figure 8. Evaluated Dipole charges using Nethercot arithmetic average (AM) formula, Nethercot geometric average (GM) formula, Pauling formula and Barbe formula of a series of molecules. Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 453 Figure 9. Comparative study of the evaluated Dipole Moment in Debye using the dipole charge of Nethercot arithmetic average (AM) formula, Nethercot geometric average (GM) formula, Pauling formula and Barbe formula and R(A‐B) of present calculation vis a vis experimental dipole moment of a series of molecules. Figure 10. Comparative study of the computed atomic polar tensor (APT) of X atom in hydrogen halides. 4. Results and discussion It is distinct from Table 1 that the new set of atomic electronegativity data exhibits perfect periodicity of periods and groups. The validity of any theoretical model is its ability to explain and correlate experimental observations. We have listed below the explanations of some interesting experimental observations using the computed electronegativity data. 1. The electronegativity data of N and Cl follow the order‐ χN > χCl. Thus the half shell stability of nitrogen atom is nicely reflected by the electronegativity data of the present calculation. 2. From Table 1, it is obvious that the atomic electronegativities of the transition metal atoms are small and increase slowly with increasing atomic number. Thus the electronegativity data of the said elements of the present calculation exhibit the expected trend. 3. Both set of electronegativity data‐ the present scale and the GC electronegativity scale, show perfect periodicity of periods and groups and are nicely correlated with each other. The R2 value of this correlation (Figure 1) is 0.892. 4. The difference of atomic electronegativity between F and Xe and that between O and Xe and also between F and Kr suggest that Xe can form compounds with F and O, and Kr can form compounds with F, but possibility of bonding between Xe and Cl is very difficult. 5. Gyftopoulos and Hatsopoulos [38] identified atomic electronegativity as minus of the thermodynamic chemical potential which implies that atomic electronegativity is the holding power of electron by an atom. The intrinsic inertness and high atomic electronegativity of Hg and Au is well known [39]. A look on the Table 1 reveals that the atomic electronegativity of Hg and Au are very high. These high values of atomic electronegativity indicate that the nuclei of Hg and Au hold their electron cloud very tightly. Hence the intrinsic inertness and high atomic electronegativity of Hg and Au are nicely correlated by the computed electronegativity data for them. 6. It is well known [39] that the actinides are electropositive and reactive. From Table 1, we can see that the atomic electronegativity values of the actinides are accordingly very small. 7. It is well established that the transition within a periodic group from an 8‐shell to an 18‐shell type of atom gives an increase in atomic electronegativity [40] because the 18 shell atoms are more compact and have a greater tendency to attract electrons expand their electronic spheres toward greater stability. From Figure 2, we see that the present computed electronegativity values of those elements satisfy these observations nicely. 8. A look on the Figure 3 reveals that the computed electronegativity values satisfy the silicon rule. 9. Figure 4 demonstrates that the electronegativity of Chalcogens follows the expected trend. 10. Figure 5 demonstrates that the electronegativities of the inert gas elements are very high. 11. From Figure 6 we can conclude that the atomic electronegativity values of H and halogens of the present work, Pearson’s work [32] and Robles and Bartolotti’s work [33] follow the expected trend of atomic electronegativity data but the GC atomic electronegativity for H and halogens (except F) show erroneous trend. 12. A look at the Figure 7 reveals that the internuclear distances of the series of heteronuclear diatomic molecules computed through the present atomic electronegativity values are very close to their spectroscopic counterparts. 13. Looking at the Figure 8 we can see that the atomic charge densities of the compounds that are predominantly ionic are nearly equal to unity and that are predominantly covalent are also very small. Thus the dipole charges computed using all of the above mentioned algorithms and the atomic electronegativity values of the present work are consistent with the nature of the bonding and also the chemico‐physical features of the compound brought under study. 14. It is distinct from the Figure 9, that the theoretical dipole moments of the ionic compounds show a nice correlation with the experimental dipole moments. But in case of covalent compounds, the computed dipoles, though scattered, fairly correlate with the experimental dipoles. Ghosh and Bhattacharyya [41] opined that because of the lone pair component of the dipoles of such molecules must vectorially couple with the bond moment component. It, therefore, transpires that there can be no good correlation between the experimental dipoles having two contributing components and the bond dipoles of molecules. From Figure 10, it is transparent that the atomic polar tensors, APTs computed using the atomic electronegativity value of the present work correlate well with the observed value but, except fluorine, the APT’s using GC electronegativity show reverse trend with the observed results. The comparison with the observed value also reveals that both the APT of present work and observed show similar trend of variation of the atomic polar tensor. 454 Islam / European Journal of Chemistry 2 (4) (2011) 448‐454 5. Conclusion We have derived the electronegativity ansatz of Gordy relying upon the electrostatic definitions of ionization energy and electron affinity and using the electronegativity ansatz of Mulliken. The newly designed scale of atomic electronegativity is found to satisfy entire sine qua non of a reasonable scale of atomic electronegativity. The unique order of atomic electronegativity of H atom and halogen family is nicely correlated in this work. We have computed four very important and useful descriptors of chemical reactivity using the atomic electronegativity values computed by us and found that in major cases the computed atomic electronegativity data produced results which close to the experimental results. The periodic behavior of the computed electronegativity data and also the correlation of important physico‐chemical properties of elements using the computed electronegativity data suggest that present method of evaluation of the atomic electronegativity of the atoms is quite successful venture. Acknowledgements We wish to express our sincere thanks to Professor Dulal Chandra Ghosh, University of Kalyani, India for valuable teaching on this subject. References [1]. Berzelius, J. J. Annals. Philo. 1813, 2, 443‐454. [2]. Pauling, L. The Nature of the Chemical Bond. 3rd Edn. Cornell University: Ithaca. NY, 1960. [3]. Pauling, L.; Yost, D. M. Proc. Nat. Acad. Sci. 1932, 18, 414‐416. [4]. Sanderson, R. T. 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