Inorganic Review

ground-state electron configuration of neutral Ir and the formal oxidation state of Ir in [IrO4]+, respectively? Treat each O atom as oxide.

[Xe] 4f14 5d7 6s2; +9

ground-state electron configuration of neutral Os (Z = 76) and the formal oxidation state of Os in OsO4, respectively? Treat each O atom as oxide.

[Xe] 4f14 5d6 6s2; +8

Neutral Fe has configuration [Ar] 3d6 4s2. Which configuration is expected for Fe2+?

[Ar] 3d6

What is the principal reason that the atomic radius decreases from La to Er across the lanthanoid series?

The 4f electrons shield poorly, so increasing nuclear charge draws the electrons inward.

Why are the sizes of Zr and Hf unusually similar, even though Hf lies below Zr in Group 4?

Filling the 4f subshell contracts Hf, offsetting much of the size increase down the group.

Which point group and set of proper rotation axes describe an ideal tetrahedral CH4 molecule?

Td; four C3 axes and three C2 axes

Which point group and symmetry elements describe an ideal trigonal-pyramidal NH3 molecule?

C3v; one C3 axis and three vertical mirror planes

Using VSEPR theory, what are the molecular geometries of ClF4+ and ClF4−, respectively?

Seesaw and square planar

Using VSEPR theory, what are the molecular geometries of BrF3 and XeF4, respectively?

T-shaped and square planar

Diethylenetriamine, H2NCH2CH2NHCH2CH2NH2, binds one metal ion through all three N atoms. How is the ligand described in this binding mode?

Tridentate and chelating

Ethylenediamine, H2NCH2CH2NH2 (en), binds one metal through both N atoms. How is each en ligand described, and what is the coordination number of Co in [Co(en)3]3+?

Bidentate and chelating; coordination number 6

The salts [CoBr(NH3)5]SO4 and [Co(SO4)(NH3)5]Br differ by exchange of a coordinated ion with a counterion. What type of isomerism is this?

Ionization isomerism

Two complexes have the same composition, but an NO2− ligand binds through N in one and through O in the other. All other ligands are unchanged. What type of isomerism is illustrated?

Linkage isomerism

For octahedral [Co(CN)6]3−, assume a strong ligand field. Which option gives the d-electron configuration, number of unpaired electrons, and LFSE including pairing energy relative to a spherical-field d6 ion? Count P for each additional electron pair.

t2g6 eg0; 0 unpaired; −2.4ΔO + 2P

For octahedral complexes, which d-electron count can give either a high-spin or a low-spin configuration as the ligand-field strength changes?

d5

Within the ideal octahedral ligand-field model, how many unpaired electrons are present in high-spin and low-spin d4 configurations, respectively?

4 and 2

Which ion lacks d–d transitions because its d subshell is full?

Zn2+ (d10)

In MnO4−, what are the formal oxidation state and d-electron count of Mn? Treat oxygen as oxide.

+7 and d0

A Latimer diagram in basic solution gives E° = +0.68 V for ClO2− → ClO− and E° = +0.42 V for ClO− → Cl2. What is E° for the overall ClO2−/Cl2 couple, rounded to two decimal places?

+0.59 V

On a Frost diagram at a fixed pH, an intermediate oxidation state lies above the straight line joining a lower and a higher oxidation state. What does this indicate?

The intermediate is thermodynamically unstable toward disproportionation into the two other states

At a fixed pH, the point for M(III) on a Frost diagram lies below the straight line joining M(II) and M(IV). What does this imply?

M(II) and M(IV) have a thermodynamic tendency to comproportionate to M(III).

reating O as O2−, which combination of iron oxidation states gives

neutral Fe3O4?

C. One Fe(II) and two Fe(III) ions

Which nuclear equation represents deuterium–tritium fusion? Superscripts denote mass numbers.

2H + 3H → 4He + 1n + energy

In one deuterium–deuterium fusion pathway, two 2H nuclei form one 3He nucleus and one other particle. Which particle conserves both mass number and nuclear charge?

A neutron, 1n

Which pair gives the balanced Haber process and methane steam-reforming reaction, respectively? For steam reforming, consider the step before the water-gas shift reaction.

N2 + 3H2 ⇌ 2NH3; CH4 + H2O ⇌ CO + 3H2

Complete steam reforming of 2 mol CH4 to CO supplies H2 for the Haber process. With excess N2, what maximum amount of NH3 can form? Exclude water-gas shift.

4 mol

At a fixed temperature, what does an effective catalyst change for a reversible reaction?

The rate of reaching equilibrium

Which set consists entirely of allotropes or structural forms of elemental carbon?

Diamond, graphite, graphene, fullerenes, carbon nanotubes

Why does graphite conduct electricity much more readily within its sheets than diamond does?

Graphite has delocalized electrons within the sheets; diamond has a wide-gap covalent network.

In toluene disproportionation over suitably modified ZSM-5, why can the xylene product stream be enriched in p-xylene?

The pore system constrains molecular transport, allowing p-xylene to diffuse more readily than the other xylene isomers.

Replacing Si4+ by Al3+ in an aluminosilicate zeolite framework creates what charge change per substitution?

One negative framework charge, balanced by an extra-framework cation

Which statement correctly describes the structures of white and black phosphorus?

White phosphorus consists of discrete tetrahedral P4 molecules; common orthorhombic black phosphorus forms puckered covalent sheets

For molecular P4O10, which pair gives its empirical formula and the oxidation state of P?

P4O10; +4

What are the oxidation states of P in P2O64− and P2O74−, respectively?

+4 and +5

Which sequence gives the ground state and the two lowest singlet excited states of O2 in order of increasing energy?

X3Σg- < a1Δg < b1Σg+

Which description of the ground electronic state of O2 is correct?

A triplet state with two unpaired electrons in separate π* orbitals

UV photolysis of CCl3F releases Cl•. Which pair of reactions regenerates Cl• and gives the net reaction O3 + O → 2O2?

Cl• + O3 → ClO• + O2; ClO• + O → Cl• + O2

Which half-equation correctly represents oxygen evolution in acidic solution?

2H2O → O2 + 4H+ + 4e−

Which statement about common orthorhombic and monoclinic sulfur is correct?

Both contain S8 rings but differ in crystal packing.

What are the formal oxidation states of S in SO32− and SO42−, respectively?

+4 and +6

Diamond has a conventional unit cell with a = b = c and α = β = γ = 90°. To which crystal system does it belong?

Cubic

Which Bravais lattice describes elemental gold under ordinary ambient conditions?

Face-centered cubic

A monatomic body-centred cubic metal has atoms at eight corners and one at the body centre. How many atoms belong to one conventional cell?

2

Which set contains only symmetry operations with an intrinsic nonzero

translation component, as encountered in periodic crystal structures?

Lattice translation, glide reflection, screw

rotation

In conventional X-ray diffraction, the incident X-rays are scattered primarily by which part of an atom?

Electrons

For a first-order reflection, the interplanar spacing is d = 3.35 Å and the X-ray wavelength is λ = 1.54 Å. Using nλ = 2d sin θ, calculate the Bragg angle θ (not 2θ) to two decimal places.

13.29°

A first-order reflection has interplanar spacing d = 2.50 Å and X-ray wavelength λ = 1.54 Å. Using nλ = 2d sin θ, calculate the detector angle 2θ to two decimal places.

35.88°

Which instrument and plotted quantities describe a conventional powder X-ray diffraction measurement?

X-ray diffractometer; diffracted intensity versus 2θ

Which information can a suitable single-crystal X-ray diffraction structure determination provide most directly?

The arrangement of atoms in the unit cell and the resulting bond lengths and molecular geometry

An [ML4] complex has four coplanar donor atoms with L–M–L angles near 90° and 180°. Which geometry is supported?

Square planar