How many electrons are present in 4f orbitals of `Gd^(2+)`

Options

A. 9
B. 8
C. 7
D. 6

Answer

To determine how many electrons are present in the 4f orbitals of the ion \( \text{Gd}^{2+} \), we can follow these steps:

### Step 1: Determine the Atomic Number of Gadolinium
The atomic number of Gadolinium (Gd) is 64.

### Step 2: Write the Electronic Configuration of Neutral Gadolinium
The electronic configuration of neutral Gadolinium (Gd) can be written as:
\[ \text{Gd: } [\text{Xe}] 6s^2 4f^7 5d^1 \]
Here, \([\text{Xe}]\) represents the electron configuration of Xenon, which accounts for the first 54 electrons.

### Step 3: Account for the Charge of the Ion \( \text{Gd}^{2+} \)
Since we are looking for the configuration of \( \text{Gd}^{2+} \), we need to remove two electrons from the neutral Gadolinium configuration. Electrons are removed from the outermost shell first, which in this case is the 6s orbital.

### Step 4: Remove Electrons from the Configuration
By removing the two electrons from the 6s orbital, the new configuration for \( \text{Gd}^{2+} \) becomes:
\[ \text{Gd}^{2+}: [\text{Xe}] 4f^7 5d^1 \]

### Step 5: Count the Electrons in the 4f Orbitals
In the configuration of \( \text{Gd}^{2+} \), we see that there are 7 electrons in the 4f orbitals.

### Final Answer
Thus, the number of electrons present in the 4f orbitals of \( \text{Gd}^{2+} \) is **7**.

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