Provide an example of how a scientific prediction related to the periodic table was tested and what the outcome was.

One example is the prediction of gallium by Mendeleev. He predicted its existence based on gaps in his periodic table and its properties. When gallium was discovered, its properties matched Mendeleev's predictions, supporting his periodic table's structure.

This answer is strong because it illustrates a specific historical example of prediction testing in science, demonstrating how empirical evidence can support theoretical frameworks. The question tests the ability to apply knowledge of historical scientific developments.