Electron Affinity and Ionization Energy

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Ava Harvey 2B
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Joined: Fri Sep 29, 2017 7:04 am

Electron Affinity and Ionization Energy

Postby Ava Harvey 2B » Wed Oct 25, 2017 9:33 pm

Hi! I was just wondering if someone could please explain to me the relationship between electron affinity and ionization energy. I know that their trend is the same or very similar throughout the periodic table, but I'm confused on what that relationship actually is and what it means. Thanks!

Dang Lam
Posts: 55
Joined: Thu Jul 27, 2017 3:01 am

Re: Electron Affinity and Ionization Energy

Postby Dang Lam » Wed Oct 25, 2017 9:41 pm

-Ionization Energy = Energy needed to remove an e-
-Election Affinity = Energy released when an e- is being added
They have the same trend because it takes a lot of energy to remove/add an e- to a stable atom, aka in this case the noble gas.

Yashaswi Dis 1K
Posts: 56
Joined: Fri Sep 29, 2017 7:04 am

Re: Electron Affinity and Ionization Energy

Postby Yashaswi Dis 1K » Wed Oct 25, 2017 10:18 pm

Yes, electron affinity is the energy that's released when an electron is added.
Ionization energy is energy needed to remove an electron.

Really important to know (maybe not for now but helpful for later too) is the following:

Electron Affinity (Mostly Exothermic)...For the first electron affinity especially for elements in group 17, the electron affinity is high as a lot of energy is released (more favorable) b/c the group 17 elements want that extra electron to have a noble-gas like configuration. Of course, as you move on to the second and third electron affinities I believe it's harder to add the extra electrons, b/c now the group 17 elements which have a noble-gas like configuration don't want any extra electron as they are satisfied with their 8 electrons (octet rule).

Ionization Energy (Almost always Endothermic I believe)...this requires a lot of energy to be put in to remove an electron as you move onto higher ionization energies, like the 4th or 5th ones for ex. b/c the electrons love the positive charge of the nucleus and as you slowly get to the core of the nucleus, it gets really hard to remove an electron, that's why you will see those big jumps between the successive ionization energies of an electron.

Hope this gives a clearer idea of the difference between the two!

Yashaswi Dis 1K
Posts: 56
Joined: Fri Sep 29, 2017 7:04 am

Re: Electron Affinity and Ionization Energy

Postby Yashaswi Dis 1K » Wed Oct 25, 2017 10:19 pm

Yes, electron affinity is the energy that's released when an electron is added.
Ionization energy is energy needed to remove an electron.

Really important to know (maybe not for now but helpful for later too) is the following:

Electron Affinity (Mostly Exothermic)...For the first electron affinity especially for elements in group 17, the electron affinity is high as a lot of energy is released (more favorable) b/c the group 17 elements want that extra electron to have a noble-gas like configuration. Of course, as you move on to the second and third electron affinities I believe it's harder to add the extra electrons, b/c now the group 17 elements which have a noble-gas like configuration don't want any extra electron as they are satisfied with their 8 electrons (octet rule).

Ionization Energy (Almost always Endothermic I believe)...this requires a lot of energy to be put in to remove an electron as you move onto higher ionization energies, like the 4th or 5th ones for ex. b/c the electrons love the positive charge of the nucleus and as you slowly get to the core of the nucleus, it gets really hard to remove an electron, that's why you will see those big jumps between the successive ionization energies of an electron.

Hope this gives a clearer idea of the difference between the two!


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