Determining stability?

[JulieAljamal1E]

5I.13 asks to determine if Cl2 or F2 is more thermodynamically stable relative to its atoms. The answer is Cl2. How is that so? We solved that the F2 reaction has an equilibrium constant of 1.2x10^-4 and the Cl2 rxn had 1.3x10^-7 Kc.

[Chem_Mod]

Essentially, the one with a lower equilibrium constant would mean that reactants are favored, showing that the reactant is relatively more stable. Thus, Cl2, the reactant in its reaction, should be more stable than F2, which has a higher equilibrium constant.