4. ELECTRONEGATIVITY For each of the following sets of atoms, rank them from lowest to highest electronegativity. a. Li, CN b. C. O, Ne c. Si, P. O d. K. Mg. P e. S. F. He

On the basis of the electronegativity values given in Fig. 12.3, indicate which is the more polar bond in each of the following pairs. msp;a.HForHClc.HBrorHClb.HClorHId.HIorHBr

Write Lewis structures for: (a) PO43 (b) ICl4 (c) SO32 (d) HONO

These are NOTlegitimate Lewisstructures (and aremissing formalcharges). Show (as inthe example) how apair of electrons canbe moved to make theLewis structurelegitimate.

G. N. Lewis developed a model for chemical bonding that you have learned in this chapter. His theory was extremely successful and is used today at all levels of chemistry, from the introductory class to the research laboratory. Why was Lewis theory so successful?

On the basis of the electronegativity values given in Fig. 12.3. indicate which is the more polar bond in each of the following pairs. msp;a.OClorOBrc.PSorPOb.NOorNFd.HOorHN

A paper published in the research Journal Science in 2007 (S. Vallina and R. Simo, Science, Vol. 315, p. 506, January 26, 2007) reported studies of dimethylsulfide (DMS), an important green-house gas that is released by marine phytoplankton. This gas represents the largest natural source of atmospheric sulfur and a major precursor of hygroscopic (i.e., cloud-forming) particles in clean air over the remote oceans, thereby acting to reduce the amount of solar radiation that crosses the atmosphere and is absorbed by the ocean. (a) Sketch the Lewis structure of dimethylsulfide, CH3SCH3, and list the bond angles in the molecule. (b) Use electronegativities to decide where the positive and negative charges lie in the molecule. Is the molecule polar? (c) The mean seawater concentration of DMS in the ocean in the region between 15 north latitude and 15 south latitude is 2.7 nM (nanomolar). How many molecules of DMS are present in 1.0 m3 of seawater?

(a) Use the VSEPR theory to predict the structure of the NNO molecule. (b) The substance NNO has a small dipole moment. Which end of the molecule is more likely to be the positive end, based only on electronegativity?

Which of the following statements is false concerning bonding? Elements with extremely different electronegativities tend to form ionic bonds with each other. In an N—O bond. electron density is greater near the O atom. An N—O bond is an example of a polar covalent band. In general, chemical bonds form to minimize energy. The bond in KBr is formed by sharing electrons.

The molecular ion S3N3 has the cyclic structure All SN bonds are equivalent. (a) Give six equivalent resonance hybrid Lewis diagrams for this molecular ion. (b) Compute the formal charges on all atoms in the molecular ion in each of the six Lewis diagrams. (c) Determine the charge on each atom in the polyatomic ion, assuming that the true distribution of electrons is the average of the six Lewis diagrams arrived at in parts (a) and (b). (d) An advanced calculation suggests that the actual charge resident on each N atom is 0.375 and on each S atom is +0.041 . Show that this result is consistent with the overall +1 charge on the molecular ion.