If you were given a sample of an unknown material, how would you determine its composition? Before turning to Properties of substances​, you can obtain a rough estimate based on the following:

• Is it a solid, a liquid or a gas in room temperature?
• Is it hard or soft?
• Is it shiny or matte?
• Can you bend it without chipping, or is it brittle?
• Does it have an odour?
• Does it conduct electricity?

By answering these questions, you know whether to turn to the left or right side of the periodic table.

• metals on the left: they are usually solid, hard, shiny, malleable, and they conduct electricity
• nonmetals on the right: they lack the conductivity of metals, and in addition to resisting sudden temperature changes, they tend to evaporate rather easily

On their border in the table, there exist a few elements, called metalloids, that feature both metallic and nonmetallic properties. For example, silicon acts like a metal in its oxide, quartz, and like a nonmetal in its silicones.