Answer:
Hydrogen = element
Carbon dioxide = compound
Water = compound
Zinc = element
Nitrogen = element
Salt = compound
Helium = element
Carbon monoxide = compound
Explanation:
An element and a compound are different when it comes to the types of atoms they possess. An element has only one type of atom while a compound has two types of atoms. For example, Hydrogen is an element because it has two atoms of the same type and that is, the "Hydrogen atom."
On the contrary, Carbon dioxide has one carbon atom and two atoms for Oxygen. Therefore, it is a compound because it has two types of atoms: Carbon atom and Oxygen atom.
Water has two atoms of Hydrogen and one atom of Oxygen. Therefore, it is a compound because it has two types of atoms: Hydrogen atom and Oxygen atom.
