### Energy Equation: Electron Affinity

Posted:

**Wed Oct 12, 2016 7:14 pm**Hi All,

I remember it was said in lecture that this is the first time change in energy is not final-initial.

The course reader mentions E= E(X)(g)-E(X-)(g). Is this neutral minus the ion? Overall, I'm just confused on why and how the final minus initial concept doesn't apply here.

-Aashi

I remember it was said in lecture that this is the first time change in energy is not final-initial.

The course reader mentions E= E(X)(g)-E(X-)(g). Is this neutral minus the ion? Overall, I'm just confused on why and how the final minus initial concept doesn't apply here.

-Aashi