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- Sodium azide is a shock-sensitive compound that releases N2 upon physical impact. The compound is used in automobile airbags. The azide ion is N3-. (a) Draw the Lewis structure of the azide ion that minimizes the formal charge (it does not form a triangle). Is it linear or bent?
Problem 1
Problem 3a
For each molecule (a)–(f), indicate how many different electron-domain geometries are consistent with the molecular geometry shown. a.
Problem 5c
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?
Problem 6a
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?
Problem 6b
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?
Problem 7a
Consider the following hydrocarbon:
a. What is the hybridization at each carbon atom in the molecule?
Problem 7b
Consider the following hydrocarbon:
b. How many 𝜎 bonds are there in the molecule?
Problem 7d
Consider the following hydrocarbon:
d. Identify all the 120° bond angles in the molecule.
Problem 8a
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?
Problem 8b
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?
Problem 10a
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?
Problem 11a1
For each of these contour representations of molecular orbitals, identify (a) the atomic orbitals (s or p) used to construct the MO (i)
Problem 11a3
For each of these contour representations of molecular orbitals, identify (a) the atomic orbitals (s or p) used to construct the MO (iii)
Problem 11b1
For each of these contour representations of molecular orbitals, identify (b) the type of MO (s or p) (i)
Problem 11b3
For each of these contour representations of molecular orbitals, identify (b) the type of MO (s or p) (iii)
Problem 11c1
For each of these contour representations of molecular orbitals, identify (c) whether the MO is bonding or antibonding (i)
Problem 16a
a. Methane (CH4) and the perchlorate ion (ClO4−) are both described as tetrahedral. What does this indicate about their bond angles?
Problem 16b
b. The NH3 molecule is trigonal pyramidal, while BF3 is trigonal planar. Which of these molecules is flat?
Problem 18
Describe the bond angles to be found in each of the following molecular structures: (a) trigonal planar, (b) tetrahedral, (c) octahedral, (d) linear.
Problem 19b
(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?
- In which of these molecules or ions does the presence of nonbonding electron pairs produce an effect on the molecular shape? (a) CO2, (b) CH2Br2, (c) OF2, (d) BCl3, (e) SF6.
Problem 21
Problem 22
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 of a molecule that has the following electron domains on its central atom: (a) four bonding domains and no nonbonding domains (b) three bonding domains and two nonbonding domains (c) five bonding domains and one nonbonding domain (d) four bonding domains and two nonbonding domains.
Problem 23
Problem 25c
Give the electron-domain and molecular geometries for the following molecules and ions: c. SF4
Problem 28a2
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.
Problem 28a1
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.
Problem 28c
The figure that follows contains ball-and-stick drawings of three possible shapes of an AF4 molecule. (c) Which of the following elements will lead to an AF4 molecule with the shape in (iii): Be, C, S, Se, Si, Xe? i.
ii.
iii.
Problem 29c
Give the approximate values for the indicated bond angles in the following molecules: (c)
Problem 30d
Give the approximate values for the indicated bond angles in the following molecules: (d)
Problem 31
Ammonia, NH3, reacts with incredibly strong bases to produce the amide ion, NH2-. Ammonia can also react with acids to produce the ammonium ion, NH4+. (a) Which species (amide ion, ammonia, or ammonium ion) has the largest H¬N¬H bond angle? (b) Which species has the smallest H¬N¬H bond angle?