91Ó°ÊÓ

How can the paramagnetism of \(\mathrm{O}_{2}\) be explained using the molecular orbital model?

Describe the bonding in \(\mathrm{SO}_{2}\) and \(\mathrm{SO}_{3}\) using the localized electron model (hybrid orbital theory). How would the molecular orbital model describe the \(\pi\) bonding in these two compounds?

Write the Lewis structure for \(\mathrm{O}_{2} \mathrm{F}_{2}\) . Predict the bond angles and hybridization of the two central oxygen atoms. Assign oxidation states and formal charges to the atoms in $\mathrm{O}_{2} \mathrm{F}_{2} .\( The compound \)\mathrm{O}_{2} \mathrm{F}_{2}$ is a vigorous and potent oxidizing and fluorinating agent. Are oxidation states or formal charges more useful in accounting for these properties of $\mathrm{O}_{2} \mathrm{F}_{2} ?$

Give the Lewis structure, molecular structure, and hybridization of the oxygen atom for \(\mathrm{OF}_{2} .\) Would you expect \(\mathrm{OF}_{2}\) to be a strong oxidizing agent like \(\mathrm{O}_{2} \mathrm{F}_{2}\) discussed in Exercise 67\(?\)

Fluorine reacts with sulfur to form several different covalent compounds. Three of these compounds are \(\mathrm{SF}_{2}, \mathrm{SF}_{4},\) and \(\mathrm{SF}_{6} .\) Draw the Lewis structures for these compounds, and predict the molecular structures (including bond angles). Would you expect \(\mathrm{OF}_{4}\) to be a stable compound?

How does the oxyacid strength of the halogens vary as the number of oxygens in the formula increases?

Explain why HF is a weak acid, whereas HCl, HBr, and HI are all strong acids.

The xenon halides and oxides are isoelectronic with many other compounds and ions containing halogens. Give a molecule or ion in which iodine is the central atom that is isoelectronic with each of the following. \(\begin{array}{ll}{\text { a. xenon tetroxide }} & {\text { d. xenon tetrafluoride }} \\ {\text { b. xenon trioxide }} & {\text { e. xenon hexafluoride }} \\ {\text {c. xenon difluoride}}\end{array}\)

For each of the following, write the Lewis structure(s), predict the molecular structure (including bond angles), and give the expected hybridization of the central atom. a. \(\mathrm{KrF}_{2} \quad\) b. \(\mathrm{KrF}_{4} \quad\) c. \(\mathrm{XeO}_{2} \mathrm{F}_{2} \quad\) d. \(\mathrm{XeO}_{2} \mathrm{F}_{4}\)

Although He is the second most abundant element in the universe, it is very rare on the earth. Why?