How did Thomson's discovery of neon's isotopes lead to the discovery of neutrons?

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

Connect the whole numbers on the periodic table to indicate what they represent?

Element before carbon on the periodic table