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Electron Affinity

Posted: Thu Oct 24, 2019 10:06 pm
by Leslie Almaraz 4G
I am still a little confused about what electron affinity is. What I understood from the lecture is that it is the energy that is released when an electron is added to a gas phase atom. How do we know an atom is in gas phase or are all atoms in gas phase?

Re: Electron Affinity

Posted: Thu Oct 24, 2019 10:59 pm
by TarynD_1I
Electron affinity is when an atom (in the gaseous phase) takes on an electron to form an anion (a negative ion). Basically, a neutral charged atom gains an electron, and the electron's negative charge makes the atom's net charge negative.

Also, the prompt will probably tell you if the atom is gaseous or not if you cannot assume its state from context.

Re: Electron Affinity

Posted: Fri Oct 25, 2019 12:27 am
by Debora Fernandez Clemente_ 4H
Why does electron affinity increase as we go towards the noble gasses?

Re: Electron Affinity

Posted: Fri Oct 25, 2019 1:03 am
by andrewcj 2C
While my high school AP Chem teacher emphasized that this is a very unscientific way to think about it, I think it makes sense to think about electron affinity as how badly a neutral atom "wants" an electron. So for elements such as fluorine, which is so close to achieving a stable noble gas electron configuration, it really "wants" an electron. However, an element like sodium is close to a noble gas configuration, but in the opposite way in that it achieves the noble gas configuration by losing an electron. Therefore, it "wants" to lose an electron and has low electron affinity. As you go from left to right across a period, the elements get closer and closer to achieving a noble gas electron configuration, so they "want" electrons more and more.

Re: Electron Affinity

Posted: Fri Oct 25, 2019 1:11 am
by Wendy 1E
Debora Fernandez Clemente_ 4H wrote:Why does electron affinity increase as we go towards the noble gasses?


Electron affinity increases as we go towards the noble gases because the elements near the noble gases have the tendency to gain an electron due to their higher nuclear charge. In order for these elements to fill their shells, it is much easier for them to gain an electron instead of losing lots of electrons.

Re: Electron Affinity

Posted: Fri Oct 25, 2019 1:17 am
by Katie Kyan 2K
Debora Fernandez Clemente_ 4H wrote:Why does electron affinity increase as we go towards the noble gasses?

The electron affinity is essentially measuring the attraction between an electron being added to a valence shell and the nucleus. Electron affinity increases from left to right across a period because the attraction of the electrons to the nucleus also increases meaning more energy is being released when an electron is being added.