Which one of the following is not a compound? A. nitrogen peroxide B. water C. chlorine D. ammonia

nitrogen peroxide
water
chlorine
ammonia

The correct answer is C. Chlorine is an element, not a compound.

A compound is a substance that is made up of two or more elements that are chemically combined. The elements in a compound are held together by chemical bonds. Chemical bonds are the forces that hold atoms together in molecules.

Nitrogen peroxide (N2O4) is a compound that is made up of two elements: nitrogen and oxygen. Water (H2O) is a compound that is made up of two elements: hydrogen and oxygen. Ammonia (NH3) is a compound that is made up of three elements: nitrogen and hydrogen.

Chlorine (Cl2) is an element. It is a yellow-green gas that is very poisonous. It is used to make bleach and other chemicals.

Here is a table that summarizes the information above:

| Option | Description |
|—|—|
| A. Nitrogen peroxide (N2O4) | A compound that is made up of two elements: nitrogen and oxygen. |
| B. Water (H2O) | A compound that is made up of two elements: hydrogen and oxygen. |
| C. Chlorine (Cl2) | An element. It is a yellow-green gas that is very poisonous. It is used to make bleach and other chemicals. |
| D. Ammonia (NH3) | A compound that is made up of three elements: nitrogen and hydrogen. |