Problem 2
Give resonance structure(s) for the hydroxide ion \([\mathrm{OH}]^{-} .\) What description of the bonding in this ion does valence bond theory give?
Problem 10
Write down five ions (cations or anions) that are isoelectronic with neon.
Problem 11
Explain whether or not the two species in each of the following pairs are isoelectronic with one another: (a) He and \(\mathrm{Li}^{+},(\mathrm{b})\left[\mathrm{Se}_{2}\right]^{2-}\) and \(\mathrm{Br}_{2} ;(\mathrm{c}) \mathrm{NO}\) and \(\left[\mathrm{O}_{2}\right]^{+}\) (d) \(\mathrm{F}_{2}\) and \(\mathrm{ClF}\) (e) \(\mathrm{N}_{2}\) and \(\mathrm{P}_{2} ;\) (f) \(\mathrm{P}^{3-}\) and \(\mathrm{Cl}^{-}\)
Problem 12
(a) Is a dipole moment a scalar or vector property? (b) Which of the following gas phase molecules are polar: \(\mathrm{Cl}_{2}, \mathrm{HBr}, \mathrm{IF}, \mathrm{BrCl}, \mathrm{H}_{2} ?\) For those which are polar, draw a diagram that depicts the direction in which the dipole moment acts.
Problem 13
Assuming that you apply "isoelectronic' in its strictest sense, which of the following species form isoelectronic pairs? Not all species have a partner: \(\mathrm{Cl}_{2}, \mathrm{CO},\left[\mathrm{O}_{2}\right]^{2-},\left[\mathrm{S}_{2}\right]^{2-}, \mathrm{F}_{2}, \mathrm{Br}_{2}, \mathrm{N}_{2}, \mathrm{NO},\left[\mathrm{O}_{2}\right]^{+}, \mathrm{O}_{2}\)
Problem 14
(a) The results of a theoretical study of HCl show that the energies of the valence \(\mathrm{Cl} 3 s\) and \(3 p\) atomic orbitals are -29 and \(-13 \mathrm{eV}\) respectively, and the \(\mathrm{H}\) \(1 s\) atomic orbital lies at \(-14 \mathrm{eV} .\) Using the data and an LCAO approach, construct an approximate MO diagram for the formation of HCl. (b) Use the MO diagram to find the bond order in HCl. Does the MO diagram indicate that HCl is diamagnetic or paramagnetic? (c) Do these last answers agree with conclusions drawn from a Lewis structure for HCl?
