XF5, where X is an element below the third period, with seven valence electrons and an electronegativity of 2.9 Geometry: Bond angle:

Successive substitution of F atoms for H atoms in the molecule NH3 produces the molecules NH2F, NHF2, and NF3. a. Draw Lewis structures for each of the four molecules. b. Using VSEPR theory, predict the geometry of each of the four molecules. c. Specify the polarity (polar or nonpolar) for each of the four molecules.

Given the bonds C N, C H, C Br, and S O, (a) which atom in each is the more electronegative? (b) which of these bonds is the most polar?

Consider the following compounds: CO2, SO2, KrF2, SO3, NF3, IF3, CF4, SF4, XeF4, PF5, TF5, and SCl6. These 12 compounds are all examples of different molecular structures. Draw the Lewis structures for each and predict the molecular structures. Predict the bond angles and the polarity of each. (A polar molecule has a net dipole moment, while a nonpolar molecule does not.) See Exercises 25 and 26 for the molecular structures based on the trigonal bipyramid and the octahedral geometries.

Write reasonable Lewis structures for the following species, none of which follow the octet rule. (a) BeCl2 (b) SeO2- (c) ClO3 (d) CH3

Consider the following molecules: SiH4, PH3, H2S. In each case, a central atom is surrounded by four electron pairs. In which of these molecules would you expect the bond angle to be less than 109.5? Explain your reasoning.

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.

Write all resonance structures of chlorobenzene, C6H5Cl, a molecule with the same cyclic structure as benzene. In all structures, keep the CCl bond as a single bond. Which resonance structures are the most important?

Clear H,C-C :0-CH, H3C – C 'o- CH3 + The Lewis structure of methyl acetate, which has one other resonance structure in which all carbons and oxygens have complete octets, is shown. Complete the resonance structure by dragging bonds, charges, and electron lone pairs to their appropriate positions.

Each Lewis structure of benzene has three C“C double bonds. Anotherhydrocarbon containing three C“C double bonds is hexatriene, C6H8. A Lewisstructure of hexatriene is   Experiments show that three of the C¬C bonds in hexatriene are shorter than theother two. Does this data suggest that hexatriene exhibits resonance structures?