Copper, silver and gold can be found in nature as the free, uncombined elements.
Correct Answer
True
True. These metals are unreactive enough that they occur as native nuggets or deposits, which is one reason they were among the first metals people used.
Category: Transition Metal Properties
Question 2
Gold and platinum resist oxidation because their reduction potentials are much lower than those of most transition metals.
Correct Answer
False
False. Gold and platinum have much higher reduction potentials than most transition metals, so their ions are easily reduced and the metals themselves are hard to oxidize. That resistance to corrosion makes them useful in jewelry and electronic contacts.
Category: Transition Metal Properties
Question 3
Across the first transition series, the number of common oxidation states rises toward the middle of the series and then falls.
Correct Answer
True
True. Early elements such as scandium have few d electrons to lose, and late elements hold their d electrons more tightly, so elements near manganese show the widest range of oxidation states.
Category: Transition Metal Properties
Question 4
The lanthanide elements typically form stable aqueous cations with a 2+ charge.
Correct Answer
False
False. The lanthanides typically form stable 3+ cations in water. Their chemistry is so similar from one element to the next that separating them is difficult.
Category: Transition Metal Properties
Question 5
Silver can be extracted from its ores by dissolving it as the [Ag(CN)2]- complex and then adding zinc to recover the metal.
Correct Answer
True
True. In this hydrometallurgical process, cyanide and oxygen dissolve the silver as a soluble complex, and zinc, a more active metal, reduces the silver ions to silver metal.
Category: Metal Production
Question 6
Steel is made by adding extra carbon to the iron from a blast furnace to make it less brittle.
Correct Answer
False
False. Iron from a blast furnace contains too much carbon, which makes it brittle; making steel removes much of that carbon. Steels contain roughly 0.04 to 2.5 percent carbon.
Category: Metal Production
Question 7
The coordination number of a metal ion equals the number of donor atoms bonded to it, not necessarily the number of ligands.
Correct Answer
True
True. A polydentate ligand bonds through several donor atoms, so a complex with three bidentate ligands has a coordination number of 6, not 3.
Category: Complex Structure
Question 8
Ethylenediamine is a monodentate ligand that binds to a metal through a single nitrogen atom.
Correct Answer
False
False. Ethylenediamine is a bidentate ligand that binds through both of its nitrogen atoms, forming a five-membered ring with the metal.
Category: Complex Structure
Question 9
An ammonia molecule acting as a ligand is called ammine in the name of a complex.
Correct Answer
True
True. Most neutral ligands keep their molecular names, but a few have special names: NH3 is ammine, H2O is aqua, CO is carbonyl and NO is nitrosyl.
Category: Naming Complexes
Question 10
In the name of a coordination compound, the anion is named before the cation.
Correct Answer
False
False. As in other ionic compounds, the cation is named first and the anion second, whether the complex ion is the cation or the anion.
Category: Naming Complexes
Question 11
Ligands in the name of a complex are listed in alphabetical order, ignoring numerical prefixes such as di- and tri-.
Correct Answer
True
True. Ligands are alphabetized by their own names before the metal is named, so tetraammine is alphabetized under a and dichloro under c.
Category: Naming Complexes
Question 12
Cis and trans geometric isomers of a complex have identical physical properties such as color and polarity.
Correct Answer
False
False. Geometric isomers usually differ in physical and chemical properties, including color, polarity, solubility and reactivity. It is enantiomers that share most physical properties.
Category: Isomerism
Question 13
In hemoglobin, each iron ion is held by heme, which acts as a tetradentate ligand.
Correct Answer
True
True. Heme binds iron through four nitrogen atoms in a flat ring, leaving positions open for the protein and for an oxygen molecule.
Category: Complexes in Nature
Question 14
Of the two geometric isomers of diamminedichloroplatinum(II), only the trans isomer is an effective anticancer drug.
Correct Answer
False
False. The cis isomer, called cisplatin, is the effective anticancer drug; the trans isomer is not effective. The difference shows how much geometry matters to biological activity.
Category: Complexes in Nature
Question 15
In its simple form, crystal field theory treats the interaction between a metal ion and its ligands as purely electrostatic, with the ligands acting as point charges.
Correct Answer
True
True. Crystal field theory ignores covalent bonding and considers only the repulsion between ligand electrons and metal d electrons, yet it still explains much about color and magnetism.
Category: Crystal Field Theory
Question 16
A low-spin octahedral complex forms when the pairing energy is greater than the crystal field splitting energy.
Correct Answer
False
False. A low-spin complex forms when the splitting energy is greater than the pairing energy, so it costs less energy to pair electrons in the lower set than to promote them to the upper set.
Category: Crystal Field Theory
Question 17
A paramagnetic substance contains unpaired electrons and is attracted into a magnetic field.
Correct Answer
True
True. Unpaired electrons give a substance a net magnetic moment, and the size of the attraction increases with the number of unpaired electrons, so magnetic measurements can count them.
Category: Color and Magnetism
Question 18
Weak-field ligands such as iodide produce a large crystal field splitting.
Correct Answer
False
False. Iodide sits at the weak end of the spectrochemical series and produces a small splitting, which favors high-spin complexes.
Category: Crystal Field Theory
Question 19
High-spin and low-spin arrangements are both possible in octahedral complexes only for ions with d4 through d7 configurations.
Correct Answer
True
True. With three or fewer d electrons, or with eight or more, there is only one way to fill the orbitals, so only d4 to d7 ions can be either high spin or low spin.
Category: Crystal Field Theory
Question 20
The complex ion [Fe(CN)6]4- is high spin with four unpaired electrons.
Correct Answer
False
False. Cyanide is a strong-field ligand, so the six d electrons of Fe2+ pair up in the lower set, giving a low-spin, diamagnetic ion with no unpaired electrons.
Category: Color and Magnetism