Question 1

How many unpaired electrons are there in the complex ion [Mn(CN)₆]^3-?

Accepted Answer

To determine the number of unpaired electrons in the complex ion, we need to first determine the oxidation state of Mn. We know that the overall charge of the complex ion is -1, and since CN^- is a charged ligand that contributes -1 charge, we can assume that Mn has an oxidation state of +1.

Next, we need to consider the electron configuration of Mn^+. Mn has a d^5 configuration, and because CN^- is a strong field ligand, it will cause the d orbitals to split into two sets of different energy levels - a lower energy set of three orbitals (t2g) and a higher energy set of two orbitals (eg).

Based on the number of electrons in each set, we can determine that Mn^+ has two unpaired electrons in the eg set. Therefore, the answer is C) 2.

Question 2

Which one of these complex ions would absorb light with the shortest wavelength?

Accepted Answer

The complex ion that would absorb light with the shortest wavelength is the one with the greatest crystal field splitting energy ($\Delta$), which typically involves ligands that are strong field ligands according to the spectrochemical series. Among the given options, the cyanide ligand (CN-) in option D is known to be a strong field ligand, leading to a larger $\Delta$ and thus requiring higher energy (shorter wavelength) light for electronic transitions.

Question 3

Which of the following complexes has optical (chiral)isomers?

Accepted Answer

The complex [Co(en)₃]³⁺ has optical isomers because the two ethylenediamine ligands are different from each other and are bound to the central cobalt ion in a way that creates a chiral center. The other complexes do not have this feature and therefore do not have optical isomers.

Question 4

Which of the following complexes has optical (chiral)isomers?

Accepted Answer

The answer of Which of the following complexes has optical...

Question 5

Which of these electron energy level patterns would absorb light with the shortest wavelength?

Accepted Answer

Electrons in the pattern D are located in higher energy levels compared to the other patterns, which means they would require more energy to excite. Therefore, electrons in pattern D would absorb light with shorter wavelengths.

Question 6

Which of these complex ions would absorb light with the longest wavelength?

Accepted Answer

The longer the wavelength of absorbed light, the lower the energy of the transition. This means we want to look for the complex ion with the lowest energy transition. In general, complexes with larger ligands have lower energy transitions because they have weaker ligand fields. Out of the choices given, only option C has a large anionic ligand (F-) which leads to a weaker ligand field and a lower energy transition. Therefore, complex C would absorb light with the longest wavelength.

Question 7

How many unpaired electrons does the manganese ion have in [Mn(CN)₆]^4-?

Accepted Answer

The answer of How many unpaired electrons does the manganese...

Question 8

Two well-known complex ions containing Ni are [Ni(H₂O)₆]²⁺, which is green, and [Ni(en)₃]²⁺, which is purple.Which one of these statements is true?

Accepted Answer

The answer of Two well-known complex ions containing Ni are...

Question 9

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Accepted Answer

The answer of In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has...

Question 10

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has six d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Accepted Answer

The answer of In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has...

Question 11

Which of these ligands produces the weakest crystal field?

Accepted Answer

The answer of Which of these ligands produces the weakest...

Question 12

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has five d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Accepted Answer

The answer of In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has...

Question 13

Labile complexes are coordination complexes that

Accepted Answer

The answer of Labile complexes are coordination complexes that
...

Question 14

The number of geometrical isomers and optical isomers of the complex ion [Co(en)₃]³⁺ are, respectively,

Accepted Answer

The complex ion [Co(en)2Br2]+, where "en" stands for ethylenediamine, a bidentate ligand, can form geometrical isomers due to the arrangement of the Br ligands (cis and trans). However, only the cis form can exhibit optical isomerism, leading to a pair of enantiomers. Therefore, there is 1 geometrical isomer (cis) that is optically active, resulting in 2 optical isomers.

Question 15

Two complex ions containing Ni are [Ni(NH₃)₆]²⁺, which is blue, and [Ni(en)₃]²⁺, which is purple.Which one of these statements is true?

Accepted Answer

The color of a complex is due to the absorption of light, and the color observed is complementary to the color absorbed. Since [Ni(en)₃]²⁺ is purple, it absorbs yellow light, which has a higher energy than the red light absorbed by the blue [Ni(NH₃)₆]²⁺.

Question 16

The ion [Co(NH₃)₆]²⁺ is octahedral and high spin.This complex is

Accepted Answer

In a high-spin octahedral complex of Co^2+ (d^7 configuration), there are 3 unpaired electrons due to the higher energy required to pair electrons in the eg orbitals compared to the energy difference between the t2g and eg orbitals.

Question 17

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Accepted Answer

Since L is a strong field ligand, it will cause a large splitting of the d orbitals into two sets of three. The lower set (t2g) will be filled with electrons, leaving the upper set (eg) empty or partially filled. In this case, there are seven d electrons, so we would expect four to occupy the t2g set and three to occupy the eg set. However, since the ligand field is strong, the energy required to pair electrons in the eg set is less than the energy required to leave them unpaired, so one of the electrons from the eg set will pair with one of the electrons from the t2g set. This leaves two unpaired electrons in the eg set, giving a total of two unpaired electrons. Therefore, the answer is (B).

Question 18

Which of these ligands produces the strongest crystal field?

Accepted Answer

CO is a strong field ligand because it is a π-donor and σ-donor ligand, and it has a lone pair of electrons that can interact with the metal d-orbitals. The other ligands listed are weaker field ligands because they are only σ-donor ligands or have weaker π-donor abilities.

Question 19

Consider the [CoCl₆]^4- ion.Determine which responses are true statements. I.The oxidation number of Co is -4. II.The coordination number of cobalt is 6. III.It is paramagnetic. IV.It is a low-spin complex.

Accepted Answer

II, III. The coordination number of cobalt in this complex is 6, given by the coordination of 4 Cl- ions and 2 H2O molecules (not explicitly shown but implied by the typical composition of such complexes). Cobalt complexes are often paramagnetic due to unpaired electrons in the d orbitals. The oxidation state of Co is not -4; it's typically +2 or +3 in such complexes, making statement I incorrect. Whether it's a high-spin or low-spin complex depends on the ligands and the metal's oxidation state, which isn't clearly defined by the information given, making IV uncertain without more context.

Question 20

A complex with the composition [MA₂B₂]X₂ is found to have no geometrical isomers.Both A and B are monodentate ligands.The structure of the complex is

Accepted Answer

The complex has the composition [MA₂B₂]X₂, where A and B are monodentate ligands. This suggests that the complex has a total of 6 ligands, which can coordinate to the central metal atom. The central metal atom is denoted by X. The absence of geometrical isomers suggests that there are no cis and trans isomers possible, hence the complex is not square planar or octahedral. Thus, the most likely geometry would be tetrahedral, where four ligands (either all A or all B) lie at the corners of a tetrahedron around the central ion, with the remaining two ligands (either all A or all B) lying perpendicular to the plane formed by the first four ligands.

Quiz 23: Transition Metal Chemistry and Coordination Compounds

How many unpaired electrons are there in the complex ion [Mn(CN) ₆]^3-?

Which one of these complex ions would absorb light with the shortest wavelength?

Which of the following complexes has optical (chiral) isomers?

Which of the following complexes has optical (chiral) isomers?

Which of these electron energy level patterns would absorb light with the shortest wavelength?

Which of these complex ions would absorb light with the longest wavelength?

How many unpaired electrons does the manganese ion have in [Mn(CN) ₆]^4-?

Two well-known complex ions containing Ni are [Ni(H₂O) ₆]²⁺, which is green, and [Ni(en) ₃]²⁺, which is purple.Which one of these statements is true?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has six d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Which of these ligands produces the weakest crystal field?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has five d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Labile complexes are coordination complexes that

The number of geometrical isomers and optical isomers of the complex ion [Co(en) ₃]³⁺ are, respectively,

Two complex ions containing Ni are [Ni(NH₃) ₆]²⁺, which is blue, and [Ni(en) ₃]²⁺, which is purple.Which one of these statements is true?

The ion [Co(NH₃) ₆]²⁺ is octahedral and high spin.This complex is

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Which of these ligands produces the strongest crystal field?

Consider the [CoCl₆]^4- ion.Determine which responses are true statements. I.The oxidation number of Co is -4. II.The coordination number of cobalt is 6. III.It is paramagnetic. IV.It is a low-spin complex.

A complex with the composition [MA₂B₂]X₂ is found to have no geometrical isomers.Both A and B are monodentate ligands.The structure of the complex is

Quiz 23: Transition Metal Chemistry and Coordination Compounds

How many unpaired electrons are there in the complex ion [Mn(CN) 6]3-?

Which one of these complex ions would absorb light with the shortest wavelength?

Which of the following complexes has optical (chiral) isomers?

Which of the following complexes has optical (chiral) isomers?

Which of these electron energy level patterns would absorb light with the shortest wavelength?

Which of these complex ions would absorb light with the longest wavelength?

How many unpaired electrons does the manganese ion have in [Mn(CN) 6]4-?

Two well-known complex ions containing Ni are [Ni(H2O) 6]2+, which is green, and [Ni(en) 3]2+, which is purple.Which one of these statements is true?

In the complex ion [ML6]n+, Mn+ has seven d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

In the complex ion [ML6]n+, Mn+ has six d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Which of these ligands produces the weakest crystal field?

In the complex ion [ML6]n+, Mn+ has five d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Labile complexes are coordination complexes that

The number of geometrical isomers and optical isomers of the complex ion [Co(en) 3]3+ are, respectively,

Two complex ions containing Ni are [Ni(NH3) 6]2+, which is blue, and [Ni(en) 3]2+, which is purple.Which one of these statements is true?

The ion [Co(NH3) 6]2+ is octahedral and high spin.This complex is

In the complex ion [ML6]n+, Mn+ has seven d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Which of these ligands produces the strongest crystal field?

Consider the [CoCl6]4- ion.Determine which responses are true statements. I.The oxidation number of Co is -4. II.The coordination number of cobalt is 6. III.It is paramagnetic. IV.It is a low-spin complex.

A complex with the composition [MA2B2]X2 is found to have no geometrical isomers.Both A and B are monodentate ligands.The structure of the complex is

How many unpaired electrons are there in the complex ion [Mn(CN) ₆]^3-?

How many unpaired electrons does the manganese ion have in [Mn(CN) ₆]^4-?

Two well-known complex ions containing Ni are [Ni(H₂O) ₆]²⁺, which is green, and [Ni(en) ₃]²⁺, which is purple.Which one of these statements is true?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has six d electrons and L is a weak field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has five d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

The number of geometrical isomers and optical isomers of the complex ion [Co(en) ₃]³⁺ are, respectively,

Two complex ions containing Ni are [Ni(NH₃) ₆]²⁺, which is blue, and [Ni(en) ₃]²⁺, which is purple.Which one of these statements is true?

The ion [Co(NH₃) ₆]²⁺ is octahedral and high spin.This complex is

In the complex ion [ML₆]ⁿ⁺, Mⁿ⁺ has seven d electrons and L is a strong field ligand.According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

Consider the [CoCl₆]^4- ion.Determine which responses are true statements. I.The oxidation number of Co is -4. II.The coordination number of cobalt is 6. III.It is paramagnetic. IV.It is a low-spin complex.

A complex with the composition [MA₂B₂]X₂ is found to have no geometrical isomers.Both A and B are monodentate ligands.The structure of the complex is