Question

Molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds. Suggest an explanation. [Section 18.2]

Short answer

Molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds because these stronger bonds provide greater stability and resistance to breakage when exposed to the high-energy radiation found in the upper atmosphere. As a result, molecules with double and triple bonds are better suited to survive and maintain their structures in the harsh conditions of the upper atmosphere.

Step-by-step solution

Understanding the types of bonds and their strengths

There are three types of covalent bonds, namely single, double, and triple bonds. A single bond consists of one sigma bond (σ), a double bond consists of one sigma bond and one pi bond (π), and a triple bond consists of one sigma bond and two pi bonds. One important fact to note is that as the number of bonds between two atoms increases, the bond strength also increases. This means that double and triple bonds are generally stronger than single bonds.

Analyzing the upper atmosphere

The upper atmosphere, which is composed mainly of the ozone layer and the ionosphere, is exposed to high amounts of radiation, especially in the form of ultraviolet (UV) and X-rays, from the sun and cosmic sources. This radiation consists of highly energetic particles that can break chemical bonds in molecules.

Stability in a high-energy environment

Due to the increased bond strength in double and triple bonds compared to single bonds, molecules that contain double and triple bonds are more stable and resistant to breakage when exposed to the high-energy radiation found in the upper atmosphere. This stability is an advantage for molecules in this environment, as less energy is required to be gained from the surrounding radiation to maintain their structure and function.

Conclusion

Molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds because these stronger bonds provide greater stability and resistance to breakage in the presence of high-energy radiation. As a result, molecules with double and triple bonds are better suited to survive and maintain their structures in the harsh conditions of the upper atmosphere.