Which of the following best describes the difference between an oxygen molecule and an ozone molecule?

• A. An oxygen molecule is a compound, while an ozone molecule is an element.
• B. An oxygen molecule contains one oxygen atom, while an ozone molecule contains two oxygen atoms.
• C. An oxygen molecule consists of two oxygen atoms (O_2), while an ozone molecule consists of three oxygen atoms (O_3).
• D. An oxygen molecule is unstable, while an ozone molecule is highly stable.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the definitions of molecules and elements. An element is a pure substance consisting of only one type of atom, while a molecule is formed when two or more atoms bond together chemically.
2. Step 2: Identify the composition of an oxygen molecule. An oxygen molecule (O_2) consists of two oxygen atoms bonded together, making it a diatomic molecule of the element oxygen.
3. Step 3: Identify the composition of an ozone molecule. An ozone molecule (O_3) consists of three oxygen atoms bonded together, forming a triatomic molecule of the element oxygen.
4. Step 4: Compare the two molecules. Both O_2 and O_3 are molecules made up solely of oxygen atoms, so both represent forms of the element oxygen, not compounds (which require different elements).
5. Step 5: Conclude the difference. The key difference is the number of oxygen atoms: O_2 has two atoms, while O_3 has three atoms, which affects their chemical properties and stability.