Chapter 2, Problem 30P

The table below gives the average composition of the Earth’s atmosphere (ppm = parts per million). Water vapour is also present in small and variable amounts.

(a) Draw the Lewis structure for ${\text{N}}_{\text{2}}\text{O}$ ensuring that each atom obeys the octet rule. (b) Use the VSEPR model to predict the molecular shapes of ${\text{SO}}_2$, ${\text{NH}}_{\text{3}}$, ${\text{N}}_{\text{2}}\text{O}$, ${\text{CH}}_4$ and ${\text{CO}}_2$. (c) Which of the gases in the table are radicals? For each of the gases you have chosen, explain how the radical nature arises. (d) ${\text{O}}_3$ (Ozone) is only present in <0.1 ppm. Nonetheless, it is a vital component of Earth‘s atmosphere. Why? (e) Draw an MO diagram for the formation of ${\text{N}}_2$ from two N atoms, using only the valence orbitals, Use the diagram to rationalize why ${\text{N}}_2$ is chemically very inert. (f) What is the relationship between the monoatomic gases in the Earth‘s atmosphere.