Coordination Chemistry

has a linear shape.
has a V-shape (angular).
has a tetrahedral shape.
has a square planar shape.

To determine the Effective Atomic Number (EAN) of the complex ion , follow these systematic steps: EAN is defined as the total number of electrons surrounding the central metal ion in a coordination complex. It is calculated using the formula:

1. Determine the Oxidation State of the Central Metal Ion:
   In the complex , ammonia ( ) is a neutral ligand (it does not contribute to the overall charge). Therefore, the oxidation state of cobalt ( ) can be determined by the overall charge of the complex.
2. Find the Number of Electrons on the Cobalt Ion:
   - Cobalt ( ) has an atomic number of 27, which means a neutral atom has 27 electrons.
   - In the oxidation state of ( ), it loses 3 electrons.
3. Determine the Number of Electrons Donated by the Ligands:
   - Each ammonia ( ) ligand donates a lone pair of electrons to the central metal ion.
   - A lone pair consists of 2 electrons.
   - There are 6 ligands in the complex.
4. Calculate the Effective Atomic Number (EAN):
   
5. Verification Using the 18-Electron Rule:
   The 18-electron rule states that transition metal complexes tend to be most stable when the total number of valence electrons around the metal center is 18. This mimics the electron configuration of the noble gas nearest to the metal.
   • For in , the EAN is 36 electrons, which suggests that it follows the 18-electron rule effectively since cobalt typically seeks to achieve a stable electron configuration through coordination.

Conclusion:
Therefore, the Effective Atomic Number (EAN) of is 36.

Step 1: Analyze the Coordination Complex.
The coordination compound is . It contains: - Two carbonyl ( ) ligands. - Two iodido ( ) ligands. - The metal ion is rhodium (Rh) in the oxidation state.

Step 2: IUPAC Naming Conventions.
- The name of the metal is "rhodium" and the oxidation state is indicated in Roman numerals as . - The ligands are named in alphabetical order. The "carbonyl" ligand (CO) is named first, followed by "iodido" (I). - The prefix "bis" is used when there are two identical ligands (in this case, iodido).

Step 3: Conclusion.
Therefore, the IUPAC name is "carbonylbisiodidorhodium(I)", corresponding to option (3).