CH225 (40%) Final Test
I.
Length of examination: 2.5 h
Examination aids allowed: calculator
Consider the eight compounds and respond to the following.
[SeOCl3]−, [BrF4]+, [ICl4]−, [SO2F]−, [BeF3]−, [ClF2]+, [AsCl4]−, [BrO3]−
(a) Using the VSEPR method of Lectures CH225.11 and CH225.12, produce clear correct structural drawings of
the ions, showing unambiguously bonds in and out of the plane of your drawing (follow examples of Lectures
CH225.11 and CH225.12). Show lone pairs on the central atom (when present); do not show any other electrons
(Note: you will lose ½ point for every shown electron pair that isn’t a lone pair on the central atom).
(b) Assign symmetry point groups to the above species.
II.
(one of the four questions in II will be on your test)
1. Determine oxidation states for all atoms in the following molecules and ions
[IF2O2]−, [SeOCl4]2−, GaHCl2(NH3), [PH2O2]−, [PF2S2]−, Mg(ClO3)2
2. Determine oxidation states for all atoms in the following molecules and ions
[BrF4]+, AsCl5, [AlH2F2]−, [BeF3]−, N2O, [ClF2]+
3. Determine oxidation states for all atoms in the following molecules and ions
[BrOF4]−, S(CH2)F4, [PHO2]2−, N(CH3)O2, [SO2F]−, XeO2(OH)4
4. Determine oxidation states for all atoms in the following molecules and ions
[PClF5]−, SOCl2, [Be(CH3)4]2−, SO2(NH3), NO2F, [SnCl4]2−
III.
(one of the four questions in III will be on your test)
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1. Respond to the following questions using the MO diagram for H2O (see above):
a) Complete the MO diagram by adding the electrons.
b) Describe all MOs as bonding, nonbonding or antibonding.
c) Name the atomic orbital of oxygen contributing to 1b2.
d) What role does 1b2 orbital play in reactions of H2O with Lewis acids?
e) Sketch the shapes (use shading when appropriate) of the following orbitals: A1 and B1 (of hydrogen), 1b2.
2. Respond to the following questions using the MO diagram for NH3 (see above):
a) Complete the MO diagram by adding the electrons
b) Describe all MOs as bonding, nonbonding or antibonding.
c) Name the atomic orbital of nitrogen that makes the main contributing to 2a1.
d) What role does 2a1 orbital play in reactions of NH3 with Lewis acids?
e) Sketch the shapes (use shading when appropriate) of the following orbitals: A1 (of hydrogen), 2a1.
3. Respond to the following questions using the MO diagram for CO (see above):
a) Complete the MO diagram by adding the electrons
b) Describe all MOs as bonding, nonbonding or antibonding.
c) Name the atomic orbitals of carbon and oxygen contributing to the HOMO of CO.
d) What role does the LUMO of CO play in the carbonyl complexes of d-metals?
e) Sketch the shapes (use shading when appropriate) of the HOMO and LUMO of CO.
4. Respond to the following questions using the MO diagram for CO2 (see above):
a) Complete the MO diagram by adding the electrons; name the HOMO and the LUMO of CO2.
b) Identify and name all bonding, nonbonding, and antibonding MO’s of CO2.
c) Name all atomic orbitals of carbon and oxygen contributing to 2σ.
d) CO2 is a Lewis acid. Which of the orbitals of CO2 participate in the reactions of CO2 with Lewis bases?
e) Sketch one of the 1π and one of the 3π orbitals of CO2.
IV.
(one of the four questions in IV will be on your test)
1. For each of the following compounds tell the total number of atomic orbitals involved in π-bonding (that should
be 0 for any species that possesses no π-bonding):
BeH2, BeF2, [BeH3]−, [BeF3]−
2. For each of the following compounds tell the total number of atomic orbitals involved in π-bonding (that should
be 0 for any species that possesses no π-bonding):
H2S, SO2, [CF3]+, [CH3]+
3. For each of the following compounds tell the total number of atomic orbitals involved in π-bonding (that should
be 0 for any species that possesses no π-bonding):
H2O, [H3O]+, BF3, BH3
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4. For each of the following compounds tell the total number of atomic orbitals involved in π-bonding (that should
be 0 for any species that possesses no π-bonding):
N2, NH3, [N3]−, BH3
V.
(eight reactions from V will be on your test)
Produce clear and unambiguous structural drawings for all products of the following acid/base reactions.
VI.
(a) SO3 + OEt2 →
(m) SiF4 + 2KF →
(b) GaH3 + C5H5N (Pyridine) →
(n) BH3 + CO →
(c) SbF5 + NaF →
(o) I2 + AsPh3 →
(d) SO3 + H2O →
(p) BF3 + Me2SO →
(e) KCl + SnCl2 →
(q) SO2 + PMe3 →
(f) AsF3 + SbF5 →
(r) I2 + SMe2→
(g) AlCl3 + AlCl3 →
(s) CO2 + NaOH →
(h) 2KCl + SnCl4 →
(t) Ag+ + 2NMe3 →
(i) Br2 + KBr →
(u) BMe3 + LiMe →
(j) SnCl4 + NH3 →
(v) SO3 + NaOH →
(k) PF5 + LiF →
(w) HCl + PMe3 →
(l) SO2 + NMe3 →
(x) BMe3 + NaH →
(one of the four questions in VI will be on your test)
1. Decide which of the two products, 1 or 2, should be more stable. Explain your choice.
BF3 + F− → product 1
BF3 + I− → product 2
2. Decide which of the two products, 1 or 2, should be more stable. Explain your choice.
AlCl3 + NH3 → product 1
AlCl3 + AsPh3 → product 2
3. Decide which of the two products, 1 or 2, should be more stable. Explain your choice.
BMe3 + NH3 → product 1
BMe3 + NEt3 → product 2
4. Decide which of the two products, 1 or 2, should be more stable. Explain your choice.
PMe3 + H+ → product 1
VII.
PF3 + H+ → product 2
1. Write a balanced reaction equation for a Brønsted acid with a Lewis base of your choice. Indicate which of the
species in your reaction is the acid and which is the base.
2. Write a balanced reaction equation for a Brønsted base with a Lewis acid of your choice. Indicate which of the
species in your reaction is the acid and which is the base.
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VIII.
(one of the four questions in VIII will be on your test)
1.
a) Consider bonding of SO2 in metal complexes A, B, C, D (shown above) and decide which of the metal centers
should be classified as ‘soft’ acids.
b) Count electrons around the metal, determine metal oxidation state and the dn number in A, B, C, D.
2.
a) Consider bonding of Me2SO in metal complexes A, B, C, D (shown above) and decide which of the metal
centers should be classified as ‘soft’ acids.
b) Count electrons around the metal, determine metal oxidation state and the dn number in A, B, C, D.
3.
a) Consider bonding of SO2 and Me2SO in metal complexes A, B, C, D (shown above) and decide which of the
metal centers should be classified as ‘soft’ acids.
b) Count electrons around the metal, determine metal oxidation state and the dn number in A, B, C, D.
4.
a) Consider bonding of SO2 and Me2SO in metal complexes A, B, C, D (shown above) and decide which of the
metal centers should be classified as ‘soft’ acids.
b) Count electrons around the metal, determine metal oxidation state and the dn number in A, B, C, D.
IX.
(one of the four questions in IX will be on your test)
1. Predict the t2gNegM electronic configuration and the number of unpaired electrons for the following octahedral
complexes: V(CO)6, (low-spin) [Co(NH3)6]3+, [TaCl6]−, [ReCl6]2−, [Ni(NH3)6]2+, [Cr(CN)6]3−
2. Predict the t2gNegM electronic configuration and the number of unpaired electrons for the following octahedral
complexes: W(CO)6, [TiF6]3−, [Mn(CN)6]2−, [CrF6]3−, (low-spin) [Co(H2O)6]3+, [RhF6]3−
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3. Predict the t2gNegM electronic configuration and the number of unpaired electrons for the following octahedral
complexes: [Fe(CN)6]3−, [CoF6]3−, [OsCl6]2−, [Cu(H2O)6]2+, [CrCl6]4−, Mo(CO)6
4. Predict the t2gNegM electronic configuration and the number of unpaired electrons for the following octahedral
complexes: [FeF6]3−, [Re(H2O)6]3+, [Mn(H2O)6]3+, (high-spin) MnF2(NH3)4, [Ti(H2O)6]3+, [Cr(NH3)6]3+
X.
(one of the three questions in X will be on your test)
1. Why Sb–X bonds in the [SbX6]3– ions are longer than those in [SbX6]– (X = Cl or Br, see below)? Rationalize the
differences with the help of the molecular orbital diagram for an octahedral main-group AX6 molecule:
2. Answer the following questions with the help of the MO diagram for an octahedral 3d-metal complex
(a) Assuming a low-spin 16-electron configuration, complete the MO diagram by adding the electrons.
(b) Name all metal orbital contributing to t2g and sketch the shape of one of them.
3. Answer the following questions with the help of the MO diagram for an octahedral 3d-metal complex
(a) Assuming a high-spin 17-electron configuration, complete the MO diagram by adding the electrons.
(b) Name all metal orbitals contributing to the eg set and sketch the shape of one of them.
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