1/ Calculate the Mulliken electronegativity of Fluorine in Pauling units (using

Question

1/ Calculate the Mulliken electronegativity of Fluorine in Pauling units (using the above equation), and compare to the Pauling electronegativity for Fluorine, which is given at Wikipedia as 3.98.

2/ Now calculate the Mulliken electronegativity of Hydrogen in Pauling units, and compare to the Pauling value of 2.20. Is there good agreement here?

3/ Finally, calculate the Mulliken electronegativity of Carbon, and compare to the Pauling value of 2.55. The reason for the c calculation is because the idea about C-H bonds are not very polar. Would the Mulliken values for electronegativity change or even reverse our prediction of C-H bond polarity?

4/What might be some reasons that the value of electronegativity between Pauling and Mulliken are sometimes quite different?

The equation Wikipedia gives for using the Mulliken concept in calculating electronegativities in Pauling units is the following, when using eV as the unit for Mulliken electronegativities rather than kJ mol1: 0.187(1E1 + EA) + 0.17 (though Wikipedia uses E, for the first ionization energy and Eea for the electron affinity) the tables in Appetxt few problems. Use the tables in Appendix B of the book (or some other reliable source) to find IE1 and EA values for the elements in the next few problems. Make sure the values for EA are defined as the energy for A>A e, and not the other way around! (The values in the book are so defined.)

Explanation / Answer

Answer:

There is a formula called the "Pauli Electronegativity Equation"

Xa - Xb = {[Ed(AB) - 1/2[Ed(AA) + Ed(BB)]}^1/2

where Xa and Xb are the electronegativities of elements a and b respectively; Ed(AB), Ed(AA), and Ed(BB) are the dissocation energies of A-B, A-A, and B-B respectively. They are all given in units of electron volts (eV). In this case, the electronegativity of hydrogen was set to 2.20 to make all electronegativities positive. Using this formula and the dissociation energies gives the corresponding electronegativities for all H-X elements.

However, there are other equations that also calculate the electronegativity and you can find a quick article about them here:
http://en.wikipedia.org/wiki/Electronega...

Hope this was of help.

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