Question

Molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds. Suggest an explanation. [Section 18.1]

Short answer

Molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds due to their greater stability under high-energy conditions, such as intense radiation and the presence of high-energy particles. This stability is mainly attributed to the stronger and shorter bonds, which make these molecules less susceptible to being broken apart and better suited to withstand the harsh conditions of the upper atmosphere.

Step-by-step solution

Understanding Single, Double, and Triple Bonds

A single bond is formed when two atoms share one pair of electrons, while a double bond involves the sharing of two pairs of electrons, and a triple bond involves the sharing of three pairs of electrons. Generally, as the number of shared electron pairs increases, the bond becomes stronger and shorter, leading to a more stable molecule.

Conditions in the Upper Atmosphere

The upper atmosphere is an environment with high-energy particles and intense radiation. Ultraviolet (UV) radiation from the Sun, for example, can split apart molecules and create highly reactive species, such as free radicals. Molecules in this region must be able to withstand these conditions and remain stable under high-energy interactions.

Stability of Molecules with Double and Triple Bonds

Molecules with double and triple bonds tend to be more stable under high-energy conditions in the upper atmosphere. Due to their shorter bond lengths and stronger bonds, they are less susceptible to being broken apart by radiation and other high-energy particles. Additionally, these molecules often have fewer overall bonds, allowing them to better withstand the energetic environment of the upper atmosphere.

Conclusion: Why Molecules Contain Double and Triple Bonds in the Upper Atmosphere

In conclusion, molecules in the upper atmosphere tend to contain double and triple bonds rather than single bonds due to their greater stability under high-energy conditions, which is mainly attributed to the stronger and shorter bonds. These characteristics make them better suited to withstand the harsh conditions of the upper atmosphere, such as intense radiation and the presence of high-energy particles.