Electronegativity vs Electron Affinity

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Pratyush Kandimalla 2O
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Joined: Wed Sep 21, 2016 3:00 pm
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Electronegativity vs Electron Affinity

Postby Pratyush Kandimalla 2O » Sat Oct 22, 2016 2:30 pm

How is Electronegativity different from electron affinity?
Why does Electron affinity have a unit?
Why doesn't Electronegativity have a unit?

danny_nguyen_3C
Posts: 14
Joined: Wed Oct 12, 2016 3:02 am

Re: Electronegativity vs Electron Affinity

Postby danny_nguyen_3C » Sat Oct 22, 2016 5:44 pm

Electron affinity is the measure of how much energy is released when a certain atom gains an electron or the amount of energy required to detach an electron from an atom. This has units because it can be scientifically measured and quantified through experimentation. On the other hand, Electronegativity is the measure of a molecule's ability to attract an electron and form a covalent bond (the higher electronegativity an electron has, the stronger it pull has on the electron). This does not have units because it can not be experimentally measured by scientist, but it derived via computations involving an atom's characteristics in the molecule.

Also, in short, electron affinity is a fixed value for an individual atom, while electronegativity is paired with molecules and the value can differentiate.

Alex Yee - 4I
Posts: 15
Joined: Wed Sep 21, 2016 2:57 pm

Re: Electronegativity vs Electron Affinity

Postby Alex Yee - 4I » Sun Oct 23, 2016 1:22 am

Also note that electronegativity usually correlates with electron affinity, as elements closer to the noble gases generally take more energy to remove an electron as well as attract electrons more powerfully. However - half-full p block elements (group 15) have one electron in each m(sub)l position, all with parallel spins, so it is harder to remove an electron in some group 15 elements than in group 16 (electron affinity), but group 16 still attracts electrons better (electronegativity).

Kiana_Shibata_2G
Posts: 24
Joined: Wed Sep 21, 2016 2:56 pm

Re: Electronegativity vs Electron Affinity

Postby Kiana_Shibata_2G » Sun Oct 23, 2016 1:02 pm

This really helped me. Thanks for clearing this up because I was confused too.

Alex Yee - 4I
Posts: 15
Joined: Wed Sep 21, 2016 2:57 pm

Re: Electronegativity vs Electron Affinity

Postby Alex Yee - 4I » Mon Oct 24, 2016 2:01 am

We both got it wrong - I just remembered to fix it on this forum. Electron affinity is the measurable energy released (or absorbed) when an atom takes another electron to become an ion. Electronegativity is the ability of an atom to attract electrons (similar, but not an experimentally derived quantity). One of the things I described - the energy required to remove an electron - is the ionization energy. Sorry for the confusion.


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