1) As bound ligands, which of the following causes the largest splitting of d-orbitals?
a. phen
b. H2O
c. I–
d. CN–
e. C2O4^2–
Answer D
2) The spectrochemical series
a. lists ligands in order from monodentate to hexadentate.
b. lists ligands in the order of their electronegativity.
c. lists coordination compounds in order of their color.
d. lists complex ions in order of their color.
e. lists ligands in order of their tendency to split d orbitals.
Answer E
1 is right.
2. I am not familiar with this particular series but you can read about it here.
http://en.wikipedia.org/wiki/Spectrochemical_series
1) The ligands that cause the largest splitting of d-orbitals are those with the highest ligand field strength. The ligand field strength depends on their ability to donate electron density to the metal ion. In general, ligands with multiple lone pairs of electrons and/or electronegative atoms have a higher ligand field strength.
Out of the options given, CN– (cyano) is the ligand with the highest ligand field strength. It has multiple lone pairs of electrons and a highly electronegative carbon atom, which allows it to donate electron density to the metal ion. Therefore, the correct answer is option d. CN–.
2) The spectrochemical series is a list of ligands in order of their tendency to split d orbitals. The ligands at the top of the series have a higher ligand field strength and cause larger energy differences between the d orbitals, resulting in greater splitting.
Therefore, the correct answer is option e. The spectrochemical series lists ligands in order of their tendency to split d orbitals.
To determine which of the given bound ligands causes the largest splitting of d-orbitals, we need to understand the concept of ligand field splitting in coordination complexes.
In coordination complexes, the presence of ligands around a central metal ion causes the degenerate (having the same energy) d-orbitals to split into different energy levels. This splitting is known as ligand field splitting and is influenced by the nature and arrangement of the surrounding ligands.
The ligands that cause the largest splitting of d-orbitals are usually those with a high negative charge or strong electron-donating ability. These ligands can interact more strongly with the central metal ion, resulting in larger energy differences between the split d-orbitals.
Let's analyze the given options:
a. phen (phenanthroline): phen is a neutral ligand and does not carry a significant negative charge. It is not expected to cause large splitting of d-orbitals.
b. H2O (water): Water is also a neutral ligand, albeit polar, and does not have a negative charge or strong electron-donating ability. Therefore, it is not expected to cause significant ligand field splitting.
c. I– (iodide ion): Iodide ion carries a negative charge and is a larger-sized ligand. Larger anionic ligands tend to cause larger splitting because they interact more strongly with the central metal ion. Therefore, I– is a potentially good candidate.
d. CN– (cyanide ion): Cyanide ion is a small, highly electronegative ligand that carries a negative charge. It can strongly interact with the central metal ion, causing significant splitting of d-orbitals. Hence, CN– is a favorable choice.
e. C2O4^2– (oxalate ion): Oxalate ion is a doubly charged ligand, but it is larger in size compared to CN–. The size of the ligand can influence the strength of interaction with the metal ion and, therefore, the extent of ligand field splitting. Hence, C2O4^2– is less likely to cause larger splitting than CN–.
Based on this analysis, the ligand that causes the largest splitting of d-orbitals among the given options is d. CN– (cyanide ion).
Moving on to the second question:
The spectrochemical series is a list of ligands in order of their tendency to split d orbitals, also known as ligand field strength. The ligands at the top of the spectrochemical series are known as strong-field ligands, while those at the bottom are called weak-field ligands.
Options a, b, and c are incorrect because they do not accurately describe the spectrochemical series.
d. "lists complex ions in order of their color" is not entirely accurate. While the color of a complex ion can be influenced by ligand field splitting, it is not the sole factor responsible for the color observed.
e. "lists ligands in order of their tendency to split d orbitals" is the correct answer. The spectrochemical series ranks ligands based on their ability to cause ligand field splitting and is an important concept in coordination chemistry.
Therefore, the correct answer to the second question is option e.