A molecule of chlorine has atoms of the same element, and a molecule of carbon dioxide has different kinds of atoms. based on this information, chlorine is and carbon dioxide is.

Based on the information, chlorine is an element while carbon dioxide is a compound.

Explanation:

Element:

The element is a molecule which contains two or more same atoms. As in the case of Cl2 molecule, it has two chlorine atoms.

Compound:

The compound is a molecule which contains two or more atoms of different types. As in the case of CO2, it contains carbon and oxygen atoms which are two different atoms.

Chlorine is an element and carbon dioxide is a compound