Why are some ions such as chloride and sodium more stable than their atoms?

What are the spectator ions in 2h+ + so42- + ca2+ + 2r → caso4 + 2h+ + 21?

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

If i can still dissolve more sugar into the solution at a certain temperature what would i call that solution