I have been looking at websites on electron affinity. My notes report it as 'energy released when an atom gains an electron. Wikipedia http://en.wikipedia.org/wiki/Electron_affinity says the amount of energy released when detaching an electron from a singly charged negative ion, i.e., the energy change for the process X- → X + e− This seems the reverse? Also on that same Wikipedia page it says you can't get negative elctron affinity values yet on good old hyperphysics http://hyperphysics.phy-astr.gsu.edu/Hbase/chemical/eleaff.html it uses a negative convention. I thought this was a modern site? Can someone clear this up? Cheers!