Electron Affinity [ENDORSED]

[Robert Estrada]

Besides the general pattern of electron affinities being highest towards the right of the periodic table, how do you determine which elements have the highest affinity such as Chlorine vs. Bromide?

[Juno Suzuki 3B]

I can't answer this, but I'm interested in knowing the answer as well.

[Chris Pleman 3E]

Usually specific values will be provided through experimental data, but for the Chlorine vs. Bromine example, Chlorine would have the greater eletron affinity, as it is above Bromine in the periodic table.

[Curtis Wong 2D]

I believe that if you take a look at the electron configuration you can also figure out whether or not the electron affinity will be greater than 0, less than 0, or if it becomes more negative. For instance, the EA becomes more negative moving down the Group 11 elements because n increases. Because n increases, the atom becomes a bigger size, and the orbital becomes bigger. Thus, it's easier to add an electron and more energy is released. And the EA for Group 12 elements are positive mainly because the orbitals are already filled, and by adding an electron, that electron will go to a new orbital 4P. Thus, that shielding given from the full orbitals and repulsion between electrons in the full orbitals make EA positive, meaning that it requires energy to keep that electron there.