Complete the statement.
Sulfur dioxide is ().
A: an elementary substance
B: a compound
You can tell whether sulfur dioxide is an elementary substance or a compound by counting the number of symbols in its chemical formula. A symbol contains either one capital letter or a capital letter followed by one or two lowercase letters.
The chemical formula for sulfur dioxide is SO2. This formula contains two symbols: S for sulfur and O for oxygen. So, the formula tells you that sulfur dioxide is made of two chemical elements bonded together.
Substances made of two or more chemical elements bonded together are compounds. So, sulfur dioxide is a compound.