Which description below best describes the difference between these two compounds?Carbon monoxideCarbon dioxideThere is a difference in the number of oxygen atoms in the compounds.There are completely different atoms in the compounds.The size of the oxygen atoms are different.There is a difference in the number of elements in the compounds.

The description that best describes the difference between these two compounds, Carbon monoxide and Carbon dioxide, is "There is a difference in the number of oxygen atoms in the compounds."

Here's why:

1. Carbon monoxide (CO) is composed of one carbon atom and one oxygen atom.
2. Carbon dioxide (CO2) is composed of one carbon atom and two oxygen atoms.

So, the difference between these two compounds is the number of oxygen atoms. The other options are incorrect because:

• There are not completely different atoms in the compounds. Both compounds contain carbon and oxygen.
• The size of the oxygen atoms are not different. The size of an atom is determined by its element, and since both compounds contain oxygen, the size of the oxygen atoms would be the same in both.
• There is not a difference in the number of elements in the compounds. Both compounds contain the same elements: carbon and oxygen.