Electron Affinity

[Alan Wu]

Why is electron affinity negative in some textbooks and positive in this one? I learned in high school that if energy is released when an electron is added to an atom, it should be represented by a negative value. So are the positive values of electron affinity in this book just the direct opposite in sign to the negative values from other sources?

[Angela Patel 2J]

I think electron affinities can be positive or negative depending on whether energy is released or used in order to form an anion.

[Julieta Serobyan4D]

I haven't looked at the textbook yet, but I am pretty sure that
first electron affinity is always negative . Well, the first electron that is taken up any atom other than a noble gas atoms or light atoms with half filled or full filled orbitals, releases energy. For the other types of atoms, they are in preferred electronic configuration, so they gain electrons, thus having a positive ∆E. It would be great if you have posted the picture of the exercise.

Hope this helps.

[CynthiaLy4F]

Electron affinity is negative when energy is released when an electron is added and positive when energy is needed in order to add an electron.

[WYacob_2C]

Electron affinity can be either negative or positive. It is defined as the energy associated with the release or addition of an electron. When an electron is added, electron affinity will be negative. On the other hand, when an electron is released, electron affinity will be positive.