Positive and Negative Electron Affinity Values

[Samantha Pedersen 2K]

Since the formula for electron affinity is (energy of neutral atom) - (energy of anion), is it correct to say that a positive value for electron affinity means that energy is released when the electron is added to the atom? And a negative value for electron affinity means that energy must be added to get the electron attached to the atom?

Thank you!

[Minahil_Tufail_3I]

Hi, I think that when electron affinity is negative, it means that energy is being released when an electron is added. I also think that when it is more negative, that means that adding an electron to the atom is more favorable. With positive electron affinity, I believe that's when energy must be added in order for an electron to be then added to an atom, meaning the atom overall is less favorable in receiving an electron.

[Ivy Tan 1E]

Hi Samantha!
I think you're right. A positive electron affinity value means that energy is being released when an electron is added to the atom. In other words, it is more energetically favorable because elements with high electron affinity are also highly electronegative, and, therefore, easily attract electrons with the strong positive charge of their nucleus. When the electron affinity value is negative, energy must be supplied to push an electron onto the atom. This is less energetically favorable, which explains why elements with low electronegativity also have low electron affinity values (it's harder for them to attract electrons). Hope this was helpful!!