Atom electronegativity

The polarizing influence of an electronegative atom decreases with the number of inteiwening rr-bonds. This is called the inductive effect and is indicated in Figure 3-6b by a progression of 6 symbols, (t is generally accepted that the inductive effect is attenuated by a factor of 2-3 by each intervening bond. The inductive ctlcct is not... 

In sorn e situation s, using this option m ay he im portan t. For exam -pic, if p orbitals on electronegative atoms irileracL with d orbitals, (as for a silicon atom bonded to an amine group), you may want to include d orbitals. 

The direction of the dipole moment is toward the more electronegative atom In the listed examples hydrogen and carbon are the positive ends of the dipoles Carbon is the negative end of the dipole associated with the C—H bond... 

Among structural formulas in which the octet rule IS satisfied for all atoms and one or more of these atoms bears a formal charge the most stable reso nance form is the one in which negative charge re sides on the most electronegative atom... 

Here we see that when the H—A bond breaks both electrons in the bond are retained by A The more electronegative atom A is the easier it becomes for the electrons to flow m Its direction... 

The strength of an acid depends on the atom to which the proton is bonded The two mam factors are the strength of the H—X bond and the electronegativity of X Bond strength is more important for atoms m the same group of the periodic table electronegativity is more important for atoms m the same row Electronegative atoms elsewhere m the molecule can increase the acidity by inductive effects... 

Oxygen is the most electronegative atom in ethanol hydrogen is the least electronegative... 

The structure of the conjugate base is more like resonance structure B than A because the nega tive charge is on the more electronegative atom (O versus S)... 

Hence, exists only when hydrogen is bonded to the most electronegative atoms. In aqueous solutions, hydrates to form H O" ion. 

Aldiough diese structures have a positive charge on a more electronegative atom, diey benefit from an additional bond which satisfies file octet requirement of the tricoordinate carbon. These carbocations are well represented by file doubly bonded resonance structures. One indication of file participation of adjacent oxygen substituents is file existence of a barrier to rotation about the C—O bonds in this type of carbocation. 

A more electronegative atom binds its electrons more tightly than a less electronegative one. Since the S, 2 process requires donation of electron density to an antibonding orbital of the reactant, high electronegativity is unfavorable. 

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