In the first IP we see that the value decreased in going from Mg to Al rather than increasing as we just said. Well the n value stayed the same but we increased the l value and that means that the penetration of the outer electron decreased. Well if the penetration decreased then the electron is mostly outside of the inner electrons and thus it is a bit easier to remove. Trends in Electron Affinity Affinity means an attraction for doing something. I have an affinity for KrispyKreme doughnuts.
Some atoms have more of an affinity for attracting an electron to themselves than other atoms.
That is right, they are forming the Noble Gas configuration which has all of the subshells full. I will talk about trends in the absolute value of the EA to get away from this controversy since what we are interested in here is trends. The similarity in trend to that of IP is easier to understand with the second convention for with that convention both process are removing an electron and the same reasoning as above applies here. That is right, it increases. We have not added another proton so the nuclear charge has not changed, but we have added an extra electron which sees a very shielded nucleus.