For each molecule (a)–(f), indicate how many different electron-domain geometries are consistent with the molecular geometry shown. a.

The molecule shown here is difluoromethane 1CH2F22, which is used as a refrigerant called R-32. (c) If the molecule is polar, which of the following describes the direction of the overall dipole moment vector in the molecule: (i) from the carbon atom toward a fluorine atom, (ii) from the carbon atom to a point midway between the fluorine atoms, (iii) from the carbon atom to a point midway between the hydrogen atoms, or (iv) from the carbon atom toward a hydrogen atom?

The following plot shows the potential energy of two Cl atoms as a function of the distance between them. (c) If the Cl₂ molecule is compressed under higher and higher pressure, does the Cl–Cl bond become stronger or weaker?

The orbital diagram that follows presents the final step in the formation of hybrid orbitals by a silicon atom. (a) Which of the following best describes what took place before the step pictured in the diagram: (i) Two 3p electrons became unpaired, (ii) An electron was promoted from the 2p orbital to the 3s orbital, or (iii) An electron was promoted from the 3s orbital to the 3p orbital?

The orbital diagram that follows presents the final step in the formation of hybrid orbitals by a silicon atom. (b) What type of hybrid orbital is produced in this hybridization?

Consider the following hydrocarbon:

a. What is the hybridization at each carbon atom in the molecule?

Consider the following hydrocarbon:

b. How many 𝜎 bonds are there in the molecule?

Consider the following hydrocarbon:

d. Identify all the 120° bond angles in the molecule.

The drawing below shows the overlap of two hybrid orbitals to form a bond in a hydrocarbon. (a) Which of the following types of bonds is being formed: (i) C¬C s, (ii) C¬C p, or (iii) C¬H s?

The drawing below shows the overlap of two hybrid orbitals to form a bond in a hydrocarbon. (b) Which of the following could be the identity of the hydrocarbon: (i) CH4, (ii) C2H6, (iii) C2H4, or (iv) C2H2?

The molecule shown here is called furan. It is represented in the typical shorthand way for organic molecules, with hydrogen atoms not shown, and each of the four vertices representing a carbon atom. e. The bond angles in furan are much smaller than those in benzene. The likely reason is which of the following? i. The hybridization of the carbon atoms in furan is different from that in benzene. ii. Furan does not have another resonance structure equivalent to the one shown here. iii. The atoms are forced to adopt smaller angles in a five-membered ring than in a six-membered ring. [Section 9.5]

The following is part of a molecular orbital energy-level diagram for MOs constructed from 1s atomic orbitals.

(a) What labels do we use for the two MOs shown?

For each of these contour representations of molecular orbitals, identify (a) the atomic orbitals (s or p) used to construct the MO (i)

For each of these contour representations of molecular orbitals, identify (a) the atomic orbitals (s or p) used to construct the MO (iii)

For each of these contour representations of molecular orbitals, identify (b) the type of MO (s or p) (iii)

For each of these contour representations of molecular orbitals, identify (b) the type of MO (s or p) (i)

For each of these contour representations of molecular orbitals, identify (c) whether the MO is bonding or antibonding (i)

a. Methane (CH4) and the perchlorate ion (ClO4−) are both described as tetrahedral. What does this indicate about their bond angles?

b. The NH3 molecule is trigonal pyramidal, while BF3 is trigonal planar. Which of these molecules is flat?

Describe the bond angles to be found in each of the following molecular structures: (a) trigonal planar, (b) tetrahedral, (c) octahedral, (d) linear.

(b) An AB₄ molecule has two lone pairs of electrons on the A atom (in addition to the four B atoms). What is the electron-domain geometry around the A atom?

Would you expect the nonbonding electron-pair domain in NH3 to be greater or less in size than the corresponding one in PH3?

In which of the following molecules can you confidently predict the bond angles about the central atom, and for which would you be a bit uncertain? Explain in each case. (a) H2S, (b) BCl3, (c) CH3I, (d) CBr4, (e) TeBr4.

Give the electron-domain and molecular geometries for the following molecules and ions: a. HCN

Give the electron-domain and molecular geometries for the following molecules and ions: c. SF4

Draw the Lewis structure for each of the following molecules or ions, and predict their electron-domain and molecular geometries: (a) AsF₃ (b) CH₃⁺ (c) BrF₃ (d) ClO₃^- (e) XeF₂ (f) BrO₂^-