Electronegativity - How is it measured?

[RyanJ]

Electronegativity - How is it measured?

 

I recently found myself asking how electronegativity is measured and frankly my standard chemistry textbook provides nothing of use on the topic.

 

What is it measured against and how it is measured?

Is it measured against Fluorine that is the most electronegative and also who standardised the system for measuring eectronegativity?

 

Any help apprectiated!

 

Cheers,

 

Ryan Jones

[woelen]

This link may give you some answers:

 

http://chemlab.truman.edu/CHEM121Labs/Electronegativity.htm

 

Electronegativity is related to bond energies. Bond energies can be measured indirectly by measuring net energy production or absorption by formation or breaking of certain bonds (although it is not easy at all to do it accurately).

[RyanJ]

This link may give you some answers:

 

http://chemlab.truman.edu/CHEM121Labs/Electronegativity.htm

 

Electronegativity is related to bond energies. Bond energies can be measured indirectly by measuring net energy production or absorption by formation or breaking of certain bonds (although it is not easy at all to do it accurately).

 

Thanks woelen! I'll read the link as soon as I get a few minutes spare

I also found a book in school that may give more insight so I'm hoping the two will explain it

 

Cheers,

 

Ryan Jones

[RyanJ]

Oh, one more question related to this topic.

 

Does electronegativity of a compound affect the products in displacement reactions?

 

Say we had KF and NaCl, would they remain the same or would we have NaF and KCl? What I mean is would the element with the greater electronegativity act like a more reactive metal would, displacing the lower electronegative element?

 

Cheers,

 

Ryan Jones

[sunspot]

The electronegativity of an atom is connected to the ability of an atom to accommodate electron density. In the case of F- or Cl- these can hold one more electron than it has nuclear protons. Charge alone can not explain electronegativity. Something has to cancel the negative charge repulsion for F- and Cl- to remain stable anions. Without getting too fancy, the EM force is the electro-magnetic force. The electro aspect of F- and Cl- are both net negative charge repulsion. As such, the lowering of magnetic force potential needs to be stronger than the increase in electro charge repulsion for these anions to be stable. Highly electronegative elements allow a higher reduction of magnetic potential within their orbitals than an increase in charge repulsion.

 

Metals have a low electronegativity and usually become cations. Cations implies less electrons than nuclear protons. In this case, electron charge repulsion within the orbitals is not a problem since there is extra nuclear positive charge. The electro aspect of the EM potential within the metal is attractive, but the magnetic aspect of EM is subtractive.

 

Gold atoms stay neutral so there is no electro attraction or electro repulsion within its orbitals. This implies a zero magnetic contribution. Silver will tarnish implying some slight magnetic repulsion that overcome charge neutrality to make a cation.