Chapter 9

Write the Lewis structures showing formal charge for the following species. (a) \(\mathrm{CN}^{-}\) (b) \(\mathrm{HCO}_{2}^{-}\)

Write the Lewis structures showing formal charge for the following species. (a) \(\mathrm{FSO}_{3}^{-}\) (b) HNC (c) \(\mathrm{SO}_{2} \mathrm{Cl}_{2}\)

Write the Lewis structures showing formal charge for the following species. (a) \(\mathrm{ClO}_{3}^{-}\) (b) NCCN (c) \(\mathrm{SOCl}_{2}\)

The connectivity of HNO could be either HNO or HON. Draw a Lewis structure for each and predict which connectivity is the more favorable arrangement.

The connectivity of \(\mathrm{H}_{3} \mathrm{CN}\) could be \(\mathrm{H}_{2} \mathrm{CNH}\) or \(\mathrm{HCNH}_{2}\) as well. Draw a Lewis structure for each of these two structures and predict which connectivity is the more favorable arrangement.

Write all possible resonance structures for the following species. Assign a formal charge to each atom. In each case, which resonance structure is the most important? (a) \(\mathrm{NO}_{2}^{-}\) (nitrogen is central) (b) ClCN

Show all possible resonance structures for each of the following molecules or ions: (a) Nitrate ion, \(\mathrm{NO}_{3}^{-}\) (b) Nitrous oxide (laughing gas), \(\mathrm{N}_{2} \mathrm{O}\) (where the bonding is in the order \(\mathrm{N}-\mathrm{N}-\mathrm{O})\)

Write all resonance structures of toluene, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}\), a molecule with the same cyclic structure as benzene. Which resonance structures are the most important?

Write all resonance structures of chlorobenzene, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl},\) a molecule with the same cyclic structure as benzene. In all structures, keep the \(\mathrm{C}-\mathrm{Cl}\) bond as a single bond. Which resonance structures are the most important?

Draw all resonance structures for methylisocyanate, \(\mathrm{CH}_{3} \mathrm{NCO}\), a toxic gas used in the manufacturing of pesticides. Which resonance structures are the most important?

Write the Lewis structures of the following molecules, and indicate whether each is an odd-electron molecule, an electron-deficient molecule, or an expanded valence shell molecule. (a) \(\mathrm{SeF}_{6}\) (b) \(\mathrm{BBr}_{3}\) (c) \(\mathrm{NO}_{2}\)

Write the Lewis structures for the following species, and indicate whether each is an odd-electron species, an electron-deficient species, or an expanded valence shell species. (a) \(\mathrm{IF}_{3}\) (b) \(\mathrm{ICl}_{4}^{-}\) (c) \(\mathrm{N}_{2}^{+}\)

Write the Lewis structures for the following species, and indicate whether each is an odd-electron species, an electron-deficient species, or an expanded valence shell species. There is only one central atom in each. (a) \(\mathrm{XeF}_{2}\) (b) \(\mathrm{BeCl}_{2}\) (c) \(\mathrm{XeO}_{2} \mathrm{~F}_{4}\) (both \(\mathrm{O}\) and \(\mathrm{F}\) are terminal atoms)

Write the Lewis structures for the following species, and indicate whether each is an odd-electron species, an electron-deficient species, or an expanded valence shell species. (a) \(\mathrm{BI}_{3}\) (b) \(\mathrm{IF}_{5}\) (c) \(\mathrm{HN}_{2}\)

Write the Lewis structures of \(\mathrm{H}_{2} \mathrm{CNH}\) and \(\mathrm{H}_{3} \mathrm{CNH}_{2}\). Predict which molecule has the greater \(\mathrm{C}-\mathrm{N}\) bond energy.

Write the Lewis structures of \(\mathrm{HNNH}\) and \(\mathrm{H}_{2} \mathrm{NNH}_{2}\). Predict which molecule has the greater \(\mathrm{N}-\mathrm{N}\) bond energy.

Acrolein has the formula \(\mathrm{CH}_{2} \mathrm{C}(\mathrm{H}) \mathrm{C}(\mathrm{O}) \mathrm{H}\). Draw its skeleton structure and Lewis structure.

Use the octet rule to predict the element (E) from the second period that would be the central atom in the following ions. (a) \(\mathrm{EF}_{4}\) (b) \(\mathrm{EF}_{4}^{+}\)

The compound disulfur dinitride, \(\mathrm{S}_{2} \mathrm{~N}_{2}\), has a cyclic structure with alternating sulfur and nitrogen atoms. Draw two Lewis structures for \(\mathrm{S}_{2} \mathrm{~N}_{2},\) one that places an octet about each atom and another that minimizes formal charges.

The compound \(\mathrm{CF}_{3} \mathrm{SF}_{5}\) was recently identified in Earth's atmosphere and is a potential greenhouse gas. If the carbon atom and sulfur atom are bonded together, what is the Lewis structure of this compound? Do both central atoms follow the octet rule?

A In the gas phase, the oxide \(\mathrm{N}_{2} \mathrm{O}_{5}\) has a structure with an \(\mathrm{N}-\mathrm{O}-\mathrm{N}\) core, with the other four oxygen atoms in terminal positions. In contrast, in the solid phase, the stable form is \(\left[\mathrm{NO}_{2}\right]^{+}\left[\mathrm{NO}_{3}\right]^{-} .\) Draw one Lewis structure of the molecular form (with \(\mathrm{N}-\mathrm{O}-\mathrm{N}\) single bonds) and all possible resonance structures of both ions observed in the solid. Remember that second-period elements never exceed an octet.

The molecule nitrosyl chloride, NOCl, has a skeleton structure of \(\mathrm{O}-\mathrm{N}-\mathrm{Cl}\). Two resonance forms can be written; write them both. Use the formal charge stability rules to predict which form is more stable.

Draw the Lewis structure and calculate the energy needed to break all of the bonds in \(1 \mathrm{~mol}\) of \(\mathrm{CH}_{3} \mathrm{NH}_{2}\).

Draw the Lewis structure of \(\mathrm{BrNO}\). Which is the more polar bond in the molecule?

Match the following three lattice energies with the three compounds LiF, KCl, and CsI. Explain your answer. \(715 \mathrm{~kJ} / \mathrm{mol} \quad 582 \mathrm{~kJ} / \mathrm{mol}\) \(1036 \mathrm{~kJ} / \mathrm{mol}\)

A Draw the Lewis structures of \(\mathrm{N}_{2} \mathrm{O}\) and \(\mathrm{NO}_{2}\). Based on these structures, predict which has the shorter \(\mathrm{N}-\mathrm{O}\) bond. Does either of these molecules contain unpaired electrons?

The reaction of \(\mathrm{XeF}_{6}\) with a limited amount of \(\mathrm{H}_{2} \mathrm{O}\) yields \(\mathrm{XeOF}_{4}\) and HF. Write the equation for this reaction; then draw the Lewis structures of the expanded valence shell molecules in the equation.

A The compound \(\mathrm{ClF}_{3}\) reacts with solid uranium to produce the volatile compounds \(\mathrm{UF}_{6}\) and ClF. \(\mathrm{ClF}_{3}\) can be used to separate uranium from plutonium, because plutonium reacts with \(\mathrm{ClF}_{3}\) to form the nonvolatile compounds \(\mathrm{PuF}_{4}\) and ClF. (a) Write equations for these two reactions. (b) Draw the Lewis structure of \(\mathrm{ClF}_{3}\). Is there anything unusual about the Lewis structure of \(\mathrm{ClF}_{3} ?\) (c) If a mixture of uranium and plutonium reacts with excess \(\mathrm{ClF}_{3}\) to produce \(43.5 \mathrm{~g} \mathrm{UF}_{6}\) and \(22.1 \mathrm{~g} \mathrm{PuF}_{4}\), what were the masses of the uranium and plutonium in the starting mixture? Use \(244 \mathrm{~g} / \mathrm{mol}\) for the molar mass of \(\mathrm{Pu}\).