Electron Affinity

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Ryan Juncker 3D
Posts: 51
Joined: Wed Sep 18, 2019 12:18 am

Electron Affinity

Postby Ryan Juncker 3D » Sun Nov 03, 2019 7:46 pm

Can someone please elaborate on the definition and purpose of electron affinity for me? Thanks

KarineKim2L
Posts: 65
Joined: Fri Aug 30, 2019 12:16 am

Re: Electron Affinity

Postby KarineKim2L » Sun Nov 03, 2019 7:50 pm

Electron affinity is how much that element wants to gain an electron. The trend for it on the periodic table is that as you move to the right, electron affinity increases, as the positive charge of the nucleus increases. However, the noble gases have very low electron affinity because they are already extremely stable due to their completely filled shell. As you move down the periodic table, the atomic radius increases, and therefore electron affinity decreases.

Julie_Reyes1B
Posts: 72
Joined: Sat Jul 20, 2019 12:16 am

Re: Electron Affinity

Postby Julie_Reyes1B » Sun Nov 03, 2019 8:01 pm

Hi,
Electron affinity simply tells you the amount of energy that is released when an electron is added to a neutral atom. A positive value means the atom releases energy, while a negative value means energy is required for the atom to accept the electron. It basically tells you how favorable it is for an atom to gain an electron. For an element with 7 valence electrons, like F and Cl, the electron affinity is high because both elements are much more stable with an extra electron. Noble gases have negative affinities because they already have full outer shells, and it would require energy for an electron to occupy a new, further away shell. Electron affinity and ionization energy follow the same trends, though electron affinity is somewhat less consistent. Electron affinity is somewhat important in giving us reasons to explain why an octet tends to be most favorable and stable.
Hope this helps!


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