Mod 1: Ionisation energy vs electronegativity - why? (1 Viewer)

[gamja]

I understand that IE is about the amount of energy needed to remove electrons and that electronegativity is the desire for an atom to gain electrons, but why do we need two things to describe essentially the same thing?

Is it still relevant to understand PT trends for yr12 chem or is it kinda irrelevant now?

 

[Masaken]

they don't describe essentially the same thing (even though their periodicity trends are the same) - rather IE is conceptually opposite to electronegativity (how a friend of mine described it), where IE describes an element giving the electrons to a reaction whereas electronegativity displays an element seeking to take electrons in the reaction (give vs take) - the lower the IE, for example --> atom is more readily inclined to be a cation as it is more willing to remove the valence electrons (as it takes less energy to do so) --> lower electronegativity (they're related and involved in the same process but not necessarily the same)

 

[wizzkids]

There are many differences between first ionisation enthalpy and electronegativity. One big difference is ionisation enthalpy is an absolute scale, measured in kilojoules per mole, whereas electronegativity is a relative scale comparing one element to another. As you know the electronegativity scale is an arbitrary number invented by Linus Pauling. The scale starts from 0.79 for francium and ends at 3.98 for fluorine. Pauling invented this scale to model the ionic and covalent character of chemical bonds between various combinations of elements. The bigger the difference in electronegativity, the more ionic the bond becomes. With this big idea, we can grasp that ionic and covalent bonds are not separate categories, they are part of a continuum of chemical bonding.