Many people noticed that some elements had similar properties, and they tried to figure out what were the rules that governed the predictability of chemical reactions. Chemists also needed reliable atomic weights in order to predict how much product could be made from a known amount of starting material. He arranged elements in triads, meant to predict properties. He was somewhat successful. Let's explore what is meant by flame tests.
Some metals give off different colors of light when they are burned.
Get a set of four metal salts in solution, a bunsen burner, and some Q-tips. Wet each Q-tip with a salt solution and hold it in the flame. Record the color you see. When you are finished, throw out the Q-tips, turn off the gas, and return the salt solutions to the center table. In the 19th century radiochemistry, radioactivity, and atomic structure became important topics to study.