D. They are composed of different kinds of elements.
A compound is a unique substance that forms when two or more elements combine chemically.
For example, the compound carbon dioxide forms when one atom of carbon combines with two atoms of oxygen.
Another example of a compound is water. It forms when two hydrogen atoms combine with one oxygen atom.
Here , Table salt is the compound sodium chloride.
Therefore,
The properties of compounds are different from the properties of the elements that form them—sometimes very different.
That's because elements in a compound combine and become an entirely different substance with its own unique properties.
Learn more about Compound here:https://brainly.com/question/14117795
#SPJ2
