An atom had a mass of 43 and it also has has 21 electrons

scandium. if you look up the number of electrons thats the periodic number and it gives you the answer

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.