The outermost valence electron in atom A experiences an effective nuclear charge of 2 and is on average 225 pm from the nucleus. The outermost valence electron in atom B experiences an effective nuclear charge of 1 and is on average 175 pm from the nucleus. Which atom (A or B) has the highest first ionization energy?

i'm assuming that the correct answer is indeed the first one/ "a"..

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.