Transition Metals: Properties, Oxidation States, and Coordination Complexes

Question 1

Which of the following is NOT a typical property of transition metals?

Accepted Answer

Low electrical conductivity

Answer

Variable oxidation states

Answer

Formation of colored ions

Question 2

In the protein hemoglobin, what is the predominant oxidation state of iron?

Accepted Answer

+3

Answer

+1

Answer

+2

Answer

+6

Question 3

Which of the following ligands has the ability to form both sigma and pi bonds with a metal ion?

Accepted Answer

CN-

Answer

H2O

Answer

NH3

Answer

Cl-

Question 4

Determine the coordination number of the metal ion in the complex [Fe(H2O)6]3+.

Accepted Answer

6

Answer

4

Answer

8

Answer

10

Question 5

Which property of transition metal ions enables their use as catalysts?

Accepted Answer

Variable oxidation states

Answer

High magnetic susceptibility

Answer

Low ionization energy

Answer

High density

Question 6

Describe the significance of the Jahn-Teller effect.

Accepted Answer

Distortion of octahedral complexes into tetragonal or square planar complexes

Answer

Increase in the stability of octahedral complexes

Answer

Decrease in the magnetic susceptibility of octahedral complexes

Answer

Lowering of the energy of tetrahedral complexes

Question 7

Which of the following is NOT a characteristic property of transition metals?

Accepted Answer

Inert nature

Answer

Variable oxidation states

Answer

Formation of colored compounds

Answer

High melting and boiling points

Question 8

Which of the following is a coordination complex of transition metals?

Accepted Answer

[Fe(H2O)6]2+

Answer

H2SO4

Answer

NaCl

Answer

CO2

Question 9

The ligands in the coordination complex [Co(NH3)4Cl2]+ are:

Accepted Answer

Both NH3 and Cl

Answer

NH3

Answer

Cl

Answer

Neither NH3 nor Cl

Question 10

Which of the following contributes to the variable oxidation states of transition metals?

Accepted Answer

Incomplete d-orbitals

Answer

Large atomic radii

Answer

High ionization energy

Answer

Low electronegativity

Question 11

Explain the influence of electronic configurations on the oxidation states of transition metals, using iron (Fe) and copper (Cu) as specific examples.

Accepted Answer

The number of d electrons in Fe and Cu determines the range of their possible oxidation states.

Answer

Fe and Cu have similar oxidation states because they belong to the same group in the periodic table.

Answer

The oxidation states of Fe and Cu are primarily affected by their atomic masses.

Answer

The stability of oxidation states in transition metals is independent of their electronic configurations.

Question 12

In coordination complexes, ligands are characterized by their ability to:

Accepted Answer

Donate electron pairs to metal ions, forming coordinate bonds

Answer

Accept electron pairs from metal ions

Answer

Bind to metal ions through only one donor atom

Answer

Have no influence on the stability of the coordination complex

Question 13

Which ligand type has the strongest field strength?

Accepted Answer

Cyanide ligands (CN-)

Answer

Aqua ligands (H2O)

Answer

Amine ligands (NH3)

Answer

Chloride ligands (Cl-)

Question 14

What type of isomerism is exhibited by the complex ion [Co(NH3)4Cl2]+?

Accepted Answer

Stereoisomerism (geometric and optical)

Answer

Structural isomerism

Answer

Ionization isomerism

Answer

Coordination isomerism

Question 15

Which transition metal is utilized as a catalyst in the Haber process?

Accepted Answer

Nickel

Answer

Iron

Answer

Copper

Answer

Zinc

Question 16

Determine the coordination number of the metal ion in the complex [Fe(CN)6]3-.

Accepted Answer

6

Answer

4

Answer

5

Answer

7

Question 17

Which electronic transition corresponds to a d-d transition?

Accepted Answer

d -> d

Answer

n -> π*

Answer

π -> π*

Answer

σ -> π*

Question 18

Provide the IUPAC name for the complex [Pt(NH3)2Cl4].

Accepted Answer

Diamminetetrachloroplatinum(II)

Answer

Dichlorotetraammineplatinum(II)

Answer

Tetraamminedichloroplatinum(II)

Answer

Dichlorobis(ammine)platinum(II)

Question 19

Predict the molecular geometry of the complex [Ni(CO)4].

Accepted Answer

Square planar

Answer

Tetrahedral

Answer

Octahedral

Answer

Trigonal pyramidal

Question 20

How does the inert pair effect impact the chemistry of heavier transition metals?

Accepted Answer

Stabilizes lower oxidation states

Answer

Enhances reducing power

Answer

Affects magnetic properties

Answer

Only occurs in the first transition series

Question 21

How do transition metals act as catalysts in chemical reactions?

Accepted Answer

They lower the activation energy and provide an alternative reaction pathway.

Answer

They react directly with reactants to form new products.

Answer

They decrease the overall enthalpy change of the reaction.

Answer

They modify the equilibrium constant of the reaction.

Question 22

What is the coordination number of a metal ion in a tetrahedral complex?

Accepted Answer

4

Answer

2

Answer

6

Answer

8

Question 23

Which of the following ligands is a strong-field ligand?

Accepted Answer

CN-

Answer

NH3

Answer

H2O

Answer

Cl-

Question 24

What is the effect of strong-field ligands on the d-orbital splitting of a metal ion?

Accepted Answer

Increases the energy difference between the d-orbitals

Answer

Decreases the energy difference between the d-orbitals

Answer

No effect on the energy difference between the d-orbitals

Answer

Reverses the energy difference between the d-orbitals

Question 25

Which of the following is a strong oxidizing agent?

Accepted Answer

MnO4-

Answer

Fe3+

Answer

Cu2+

Answer

Zn2+

Question 26

What is the coordination number of the metal ion in the complex ion [Fe(CN)6]4-?

Accepted Answer

6

Answer

4

Answer

8

Answer

12

Question 27

What is the IUPAC name of the compound K2[PtCl6]?

Accepted Answer

Potassium hexachloroplatinate(IV)

Answer

Potassium hexachloroplatinate(II)

Answer

Dipotassium hexachloroplatinate(IV)

Answer

Dipotassium hexachloroplatinate(II)

Question 28

Which of the following ligands is a strong-field ligand?

Accepted Answer

CN-

Answer

NH3

Answer

H2O

Answer

Cl-

Question 29

Which of the following is a characteristic property of transition metals?

Accepted Answer

Ability to exhibit variable oxidation states

Answer

Low melting point

Answer

Poor thermal conductivity

Answer

High density

Question 30

In transition metal complexes, which oxidation state is most commonly observed for iron?

Accepted Answer

+2 or +3

Answer

+4 or +6

Answer

+1 or +4

Answer

+3 or +5

Question 31

Identify the strong field ligand in the following options:

Accepted Answer

CN-

Answer

NH3

Answer

Cl-

Answer

H2O

Question 32

What is the molecular geometry of the complex ion [Cu(NH3)4]2+?

Accepted Answer

Square planar

Answer

Tetrahedral

Answer

Trigonal planar

Answer

Octahedral

Question 33

Which of the following reactions demonstrates the oxidizing properties of transition metals?

Accepted Answer

MnO4- + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O

Answer

Cu2+ + 2Cl- → CuCl2

Answer

Ag+ + 2NH3 → [Ag(NH3)2]+

Answer

Fe3+ + SCN- → [Fe(SCN)]2+

Question 34

What is the primary role of transition metals in biological systems?

Accepted Answer

Acting as cofactors in various enzymes

Answer

Acting as hormones

Answer

Functioning as neurotransmitters

Answer

Serving as structural components of proteins

Question 35

Which of the following is an example of a heterogeneous catalyst?

Accepted Answer

Nickel catalyst used in hydrogenation reactions

Answer

Enzymes used in biological reactions

Answer

Hydrochloric acid used in esterification reactions

Answer

Sodium hydroxide used in saponification reactions

Question 36

Determine the correct IUPAC name for the coordination complex [Co(NH3)5Cl]2Cl.

Accepted Answer

Pentaamminechlorocobalt(III) chloride

Answer

Hexaamminecobalt(III) chloride

Answer

Tetraamminechlorocobalt(II) chloride

Answer

Triamminechlorocobalt(IV) chloride

Question 37

Which statement about transition metals is incorrect?

Accepted Answer

All transition metals are highly reactive.

Answer

Transition metal ions often form colored solutions.

Answer

Transition metals are effective catalysts.

Answer

Transition metals exhibit variable oxidation states.

Question 38

Which of the following transition metals is widely used in catalytic converters to reduce harmful emissions from vehicles?

Accepted Answer

Platinum (Pt)

Answer

Silver (Ag)

Answer

Cobalt (Co)

Answer

Iron (Fe)

Question 39

What is the oxidation state of manganese (Mn) in the compound potassium permanganate (KMnO₄)?

Accepted Answer

+7

Answer

+2

Answer

+4

Answer

+6

Question 40

Which type of bonding is involved in the formation of coordination complexes?

Accepted Answer

Coordinate covalent bonding

Answer

Hydrogen bonding

Answer

Ionic bonding

Answer

Metallic bonding

Question 41

What is the coordination number of the central metal ion in the complex tetraamminecopper(II) ion ([Cu(NH₃)₄]²⁺)?

Accepted Answer

4

Answer

8

Answer

2

Answer

6

Question 42

Which of the following ligands is classified as a bidentate ligand?

Accepted Answer

Ethylenediamine (en)

Answer

Chloride ion (Cl⁻)

Answer

Water (H₂O)

Answer

Ammonia (NH₃)

Question 43

Which transition metal ion is responsible for the blue color observed in copper(II) sulfate solutions?

Accepted Answer

Cu²⁺

Answer

Mn²⁺

Answer

Zn²⁺

Answer

Fe²⁺

Question 44

What is the systematic name of the complex ion [Fe(CN)₆]³⁻?

Accepted Answer

Hexacyanoferrate(III) ion

Answer

Hexacyanocobaltate(III) ion

Answer

Hexacyanoferrate(II) ion

Answer

Hexacyanocobaltate(II) ion

Question 45

Which statement about coordination complexes is incorrect?

Accepted Answer

Coordination complexes are always colorless.

Answer

Coordination complexes involve a metal ion surrounded by ligands.

Answer

Ligands donate electron pairs to the metal ion, forming coordinate covalent bonds.

Answer

Coordination complexes can be charged or neutral.

Question 46

What is a primary role of transition metals in biological systems?

Accepted Answer

Acting as cofactors in enzymes

Answer

Serving as the primary building blocks of proteins

Answer

Forming the main component of cell membranes

Answer

Transporting oxygen in the blood