91Ó°ÊÓ

The phosphate ion \(\left(\mathrm{PO}_{4}^{3-}\right)\) is part of our DNA. The corresponding nitrogen-containing oxoanion, \(\mathrm{NO}_{4}^{3-},\) is not chemically stable. Draw Lewis structures that show any resonance forms of both oxoanions.

Which of the following chlorine oxides are odd-electron molecules? (a) \(\mathrm{Cl}_{2} \mathrm{O}_{7} ;\) (b) \(\mathrm{Cl}_{2} \mathrm{O}_{6} ;\) (c) \(\mathrm{ClO}_{4} ;\) (d) \(\mathrm{ClO}_{3}\) (e) \(\mathrm{ClO}_{2}\)

Water vapor in the atmosphere contributes more to the greenhouse effect than carbon dioxide, yet water vapor is not considered an important factor in climate change. Propose a reason why.

How does the high-temperature conversion of limestone \(\left(\mathrm{CaCO}_{3}\right)\) to lime (CaO) during the production of cement contribute to climate change?

Argon is the third most abundant species in the atmosphere. Why isn't it a greenhouse gas?

Which \(\mathrm{C}-\) O bond has a higher stretching frequency: the one in CO or the one in \(\mathrm{CH}_{2} \mathrm{O}\) ? Explain your selection.

Use formal charges to predict whether the atoms in hypochlorous acid are arranged HOCl or HC1O.

Chemical Weapons Draw the Lewis structure of phosgene, \(\mathrm{COCl}_{2},\) a poisonous gas used in chemical warfare during World War I.

Plot the electronegativities of elements with \(Z=3\) to \(9(y \text { -axis) versus their first ionization energy ( } x\) -axis). Is the plot linear? Use your graph to predict the electronegativity of neon, whose first ionization energy is \(2081 \mathrm{kJ} / \mathrm{mol}.\)

In the typical Lewis structure of \(\mathrm{BF}_{3}\) there are only six valence electrons on the boron atom and each \(\mathrm{B}-\mathrm{F}\) bond is a single bond. However, the length and strength of these bonds indicate that they have a small measure of doublebond character-that is, their bond order is slightly greater than 1. a. Draw a Lewis structure of \(\mathrm{BF}_{3}\), including all resonance structures, in which there is one \(\mathrm{B}=\mathrm{F}\) double bond. b. What is the formal charge on the \(\mathrm{B}\) atom, and what is the average formal charge on each \(\mathrm{F}\) atom? c. Based on formal charges alone, what should be the bond order of each \(\mathrm{B}-\mathrm{F}\) bond in \(\mathrm{BF}_{3} ?\) d. What factor might support a bond order slightly greater than \(1 ?\)