[mana]

hi all
does electronegativity vary in different molecules such as PCl₃ or PF₅?

[chenbeier]

Yes it does. Fluorine is more electronegative as chlorine.

[mana]

Yes it does. Fluorine is more electronegative as chlorine.

thanks, is the electronegativity of P is different in PCl₃ and PF₅ too?

[Borek]

Electronegativity is a property of an element, doesn't depend on what molecule the atom is in.

[AWK]

Electronegativity is not a directly measured property. There are several different approaches to assessing it. Look at the first historically. Pauling determined the electronegativity difference for a particular bond, and then arbitrarily assumed the electronegativity value for one element. He determined a lot of such differences and therefore had to average the determined values. According to Pauling, electronegativity is not a value for a specific bond, but for a specific element that allows us to roughly predict some of the properties of chemical compounds.