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Electronegativity, symbolized as χ, is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. [1] An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the ...
Electronegativity is not a uniquely defined property and may depend on the definition. The suggested values are all taken from WebElements as a consistent set. Many of the highly radioactive elements have values that must be predictions or extrapolations, but are unfortunately not marked as such.
A list of the electron affinities was used by Robert S. Mulliken to develop an electronegativity scale for atoms, equal to the average of the electrons affinity and ionization potential. [2] [3] Other theoretical concepts that use electron affinity include electronic chemical potential and chemical hardness.
There are two possible structures for hydrogen cyanide, HCN and CNH, differing only as to the position of the hydrogen atom. The structure with hydrogen attached to nitrogen, CNH, leads to formal charges of -1 on carbon and +1 on nitrogen, which would be partially compensated for by the electronegativity of nitrogen and Pauling calculated the net charges on H, N and C as -0.79, +0.75 and +0.04 ...
This connection comes from the Mulliken electronegativity scale. By inserting the energetic definitions of the ionization potential and electron affinity into the Mulliken electronegativity, it is seen that the Mulliken chemical potential is a finite difference approximation of the electronic energy with respect to the number of electrons, i.e.,
The polar substituent constants are similar in principle to σ values from the Hammett equation, as an increasing value corresponds to a greater electron-withdrawing ability. Bent's rule suggests that as the electronegativity of the groups increase, more p character is diverted towards those groups, which leaves more s character in the bond ...
Pauling estimated that an electronegativity difference of 1.7 (on the Pauling scale) corresponds to 50% ionic character, so that a difference greater than 1.7 corresponds to a bond which is predominantly ionic. [10] Ionic character in covalent bonds can be directly measured for atoms having quadrupolar nuclei (2 H, 14 N, 81,79 Br, 35,37 Cl or ...
when the electronegativity difference between two bonded atoms is very small (as in H 3 PO 3). Two almost equivalent pairs of oxidation states, arbitrarily chosen, are obtained for these atoms. when an electronegative p-block atom forms solely homonuclear bonds, the number of which differs from the number of two-electron bonds suggested by rules.