It gains or loses electrons to become like the Noble gases having 8 valence electrons to become the most stable.
The answer is 1.5e+6. Hope this helped!
1.24973017189471 is probably the answer to your equation
I think the one that cause the equilibrium to shift would be :
3. adding a noble gas
Adding the noble gas will add more concentration to the KNO3, which will create different amount of equilibrium
hope this helps