Compound is a substance made up of atoms of two or more different element joined by chemical bonds. Compounds are formed when atoms of 2 or more elements combine chemically. They bond in order for each atom to be satisfied-stable.
An -ate or -ite at the end of a compound name usually indicates that the compound contains Oxygen atoms.
For example; sulfite (SO3^2-), Nitrite (NO2-), Sulfate, (SO3^2-) and nitrate, (NO3-) etc, you realize that each has an oxygen atom.