Step-by-step explanation:
An element is defined as a substance that contains same type of atoms. An element can never be broken down into its constituent particles.
For example, a spoon made up of only copper metal will contain only atoms of copper.
A compound is defined as a substance in which atoms chemically combine together in a fixed ratio by mass.
For example,
is a compound.
A compound can be broken down into its constituent particles by chemical means.
therefore, we can conclude that given unknown substance be classified as compound.