There are three possible structures for PCl2F3 with phosphorus as the central atom. Draw them and discuss how measurements of dipole moments could help distinguish among them.

Write a Lewis structure for the amide ion, NH2─, and assign formal charges to each atom.

Methanethiol, CH3SH, has a substantial dipole moment (μ = 1.52) even thoughcarbon and sulfur have identical electronegativities. Explain.

Chloral, Cl3C—CH=O, reacts with water to form the sedative and hypnotic agent chloral hydrate, Cl3C—CH(OH)2. Draw Lewis structures for these substances, and describe the change in molecular shape, if any, that occurs around each of the carbon atoms during the reaction.

Carbon, nitrogen, and oxygen form two different polyatomic ions: cyanate ion (NCO) and fulminate ion (CNO). Write Lewis structures for each anion, including near-equivalent resonance structures (do not add any arrows between structures) and indicating formal charges. The isocyanate ion also has two near-equivalent structures, but the formal charge on the nitrogen attom cannot be reduced to zero: Cyanate ion (NCO)

Does your molecular exhibit resonance? If so, show all possible forms. Does your molecule have any isomers? If so, show Lewis structures of them as well. for CH3CH2OH

Draw the Lewis structure of HClO₃ (with minimized formal charges) and then choose the appropriate pair of molecular geometries of the two central atoms. Your answer choice is independent of the orientation of your drawn structure.

Hydrogen cyanide can be catalytically reduced with hydrogen to form methylamine. Use Lewis structures and bond energies to determine ΔH°rxn for HCN(g) + 2 H2(g) ⟶ CH3NH2(g)

Formamide, HC(O)NH2, is prepared at high pressures from carbon monoxide and ammonia, and serves as an industrial solvent (the parentheses around the O indicate that it is bonded only to the carbon atom and that the carbon atom is also bonded to the H and the N atoms). Two resonance forms (one with formal charges) can be written for formamide. Write both resonance structures, and predict the bond angles about the carbon and nitrogen atoms for each resonance form. Are they the same? Describe how the experimental determination of the HNH bond angle could be used to indicate which resonance form is more important.

It is possible to write a simple Lewis structure for the SO42- ion, involving only single bonds, which follows the octet rule. However, Linus Pauling and others have suggested an alternative structure, involving double bonds, in which the sulfur atom is surrounded by six electron pairs. (a) Draw the two Lewis structures. (b) What geometries are predicted for the two structures? (c) What is the hybridization of sulfur in each case? (d) What are the formal charges of the atoms in the two structures?