(c) With what neutral homonuclear diatomic molecules are the NO+ and NO- ions isoelectronic (same number of electrons)? With what neutral homonuclear diatomic molecule is the NO- ion isoelectronic (same number of electrons)?

Azo dyes are organic dyes that are used for many applications, such as the coloring of fabrics. Many azo dyes are derivatives of the organic substance azobenzene, C12H10N2. A closely related substance is hydrazobenzene, C12H12N2. The Lewis structures of these two substances are

(Recall the shorthand notation used for benzene.) (b) How many unhybridized atomic orbitals are there on the N and the C atoms in each of the substances? How many unhybridized atomic orbitals are there on the N and the C atoms in hydrazobenzene?

The figure that follows contains ball-and-stick drawings of three possible shapes of an AF4 molecule. (a) For each shape, give the electron-domain geometry on which the molecular geometry is based. i.

The figure that follows contains ball-and-stick drawings of three possible shapes of an AF4 molecule. (a) For each shape, give the electron-domain geometry on which the molecular geometry is based. iii.

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 (c) whether the MO is bonding or antibonding (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)

The figure that follows contains ball-and-stick drawings of three possible shapes of an AF4 molecule. (a) For each shape, give the electron-domain geometry on which the molecular geometry is based. ii.

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

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?

One of the 2p orbitals with phases is shown in the figure.

a. Which 2p orbital is it?

b. Which of the statements about the orbital is or are true?

i. The two lobes are equal in size but opposite in sign.

ii. The probability of finding an electron is positive in one direction and negative in the opposite direction.

iii. The phase information for the orbital is lost when the wave function is squared. [Section 9.8]

The figures show two different possible combinations of two 2p atomic orbitals with phases to form a molecular orbital. For each of these figures

a. identify whether it represents constructive or destructive addition of the two atomic orbitals, and

b. identify whether the resulting molecular orbital will be a 𝜎, 𝜎∗, 𝜋, or 𝜋∗ MO. [Section 9.8]

An AB2 molecule that satisfies the octet rule has only A─B single bonds.

a. What is the electron-domain geometry of the molecule?

b. What is the molecular geometry of the molecule?

c. Do all AB2 molecules that satisfy the octet rule have this same molecular geometry?

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?

For a particular AB3 molecule, all the B─A─B bond angles are roughly 109°.

a. What is the molecular geometry of the molecule?

b. What is the electron-domain geometry of the molecule?

c. How many nonbonding electron domains are on the atom A?

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?