18) Which two ions have the same electron configuration in the ground state? A) Rb+ and Cs+
B) Ba2+ and I-
C) Se2+ and I-
D) Fe2+ and Fe3+

you need to have a picture of the atom that way we can answer it

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.

the enthalpy change that occurs in a system when matter is transformed by a given chemical reaction, when all reactants and products are in their standard states.