Select the elementary substance.
A: chloromethanol (CH3ClO)
B: sulfur dioxide (SO2)
C: radon (Rn)
Look at the chemical formula for each substance, and count the number of symbols in the formula. Then, decide if the substance is an elementary substance. The chemical formula for sulfur dioxide contains two symbols: S for sulfur and O for oxygen. So, sulfur dioxide is made of two chemical elements bonded together. Substances that are made of two or more chemical elements bonded together are compounds. So, sulfur dioxide is a compound, not an elementary substance. The chemical formula for radon contains one symbol: Rn. So, radon is made of one chemical element. Substances that are made of one chemical element are elementary substances. So, radon is an elementary substance. The chemical formula for chloromethanol contains four symbols: C for carbon, H for hydrogen, Cl for chlorine, and O for oxygen. So, chloromethanol is made of four chemical elements bonded together. Substances that are made of two or more chemical elements bonded together are compounds. So, chloromethanol is a compound, not an elementary substance.