Final answer:
An ozone molecule contains three oxygen atoms, denoted as O3. Ozone forms a protective layer in the stratosphere, shielding living organisms from UV radiation. At ground level, however, it is considered a harmful pollutant.
Step-by-step explanation:
An ozone molecule, often symbolized as O3, is comprised of three oxygen atoms. This molecular composition is quite different from the diatomic oxygen molecule, O2, which is commonly found in Earth's atmosphere and is essential for life. Ozone is a unique and unstable form of oxygen that plays a crucial role in the Earth's stratosphere, where it forms a layer that protects living organisms by absorbing the majority of the sun's harmful ultraviolet radiation. Despite ozone's beneficial role in the stratosphere, it can be harmful at ground level, acting as a pollutant that can cause respiratory problems and other health issues.
The ozone molecule is bent and contains a resonance structure that is necessary to describe its bonding, making it a heavier molecule of oxygen. Constantly formed and destroyed in the stratosphere, ozone molecules maintain a balance that has remained relatively stable over the decades. This cycle of ozone at different altitudes results in either a protective layer or a potential hazard, depending on its location in the Earth's atmosphere.