Describe the bonding in [RhBr₄]^- using the valence bond theory. Draw the orbital diagrams for both the free and complex metal ions. Determine the number of electrons that are unpaired and the hybrid orbital used for bonding in the complex.

Cisplatin is used for various cancer treatments. Its formula is cis-[Pt(NH₃)₂Cl₂] and has a square planar geometry. Provide the crystal-field splitting energy diagram for cisplatin and determine the number of unpaired electrons.

Identify the hybridization of the central metal ion in the complex [CoBr₄]^2– and determine the number of unpaired electrons. [CoBr₄]^2– adopts a tetrahedral geometry.

Consider the following chromium complex ions and their wavelength of maximum absorptions. List the ligands in a spectrochemical series from strongest-field to weakest-field ligand. 

For a specific transition metal and set of ligands, which geometry has a lower crystal-field splitting energy (Δ)?

Draw the crystal field energy-level diagram and determine the number of unpaired electrons in each of the following complex ions:

(i) [Mn(CN)₆]^4–

(ii) [Cr(H₂O)₆]³⁺

(iii) [MoCl₆]³⁻

The complete reaction of molybdenum metal with 1.0 M H₂SO₄ in the absence of air produced a blue solution and a colorless gas. Upon the addition of excess KNO₂, the solution changed color and its paramagnetism decreased. What is the reason for this observation?

Consider the complex with the formula K[Co(NH₃)₆](CO₃)₂.

i. Provide the name of the compound.

ii. Calculate the oxidation number of Co.

iii. Sketch its crystal field energy-level diagram.

iv. Classify the complex as either high-spin or low-spin.

v. Identify the number of unpaired electrons, if any

Those whose lobes point directly at the ligands or those whose lobes do not–which set of d-orbitals will have higher energy when ligands approach a central metal ion?

In a square planar geometry, which d orbitals have lobes that point directly between the ligands?

Draw the filled crystal-field energy-level diagram of the complex [CoCl₄]^2- (tetrahedral).

Draw the crystal field energy-level diagram for the below-given tetrahedral complex. How many unpaired electrons are present?

• [CoCl₄]²⁻

Draw the crystal field energy-level diagram for the below-given square planar complex. How many unpaired electrons are present?

[Pt(H₂O)₄]²⁺