How many unpaired electrons ae in a `Fe^(2+)` ion in the ground state?

Options

A. 0
B. 2
C. 4
D. 6

Answer

To determine the number of unpaired electrons in the `Fe^(2+)` ion in its ground state, we can follow these steps:

### Step 1: Determine the Atomic Number of Iron (Fe)
Iron (Fe) has an atomic number of 26. This means it has 26 electrons in its neutral state.

### Step 2: Write the Electronic Configuration of Neutral Iron (Fe)
The electronic configuration of neutral iron can be written as:
- `Fe: [Ar] 4s² 3d⁶`
Where `[Ar]` represents the electron configuration of Argon, which accounts for the first 18 electrons.

### Step 3: Determine the Electronic Configuration of `Fe^(2+)`
When iron loses two electrons to form the `Fe^(2+)` ion, it loses the two 4s electrons first. Therefore, the electronic configuration for `Fe^(2+)` becomes:
- `Fe^(2+): [Ar] 4s⁰ 3d⁶`

### Step 4: Visualize the Electron Arrangement in the 3d Orbital
The 3d subshell can hold a maximum of 10 electrons. In the case of `Fe^(2+)`, we have 6 electrons in the 3d subshell. The arrangement of these electrons can be visualized as follows:
- 3d: ↑↓ ↑↓ ↑↓ ↑ ↑ (where ↑ represents an unpaired electron and ↓ represents a paired electron)

### Step 5: Count the Unpaired Electrons
From the arrangement above, we can see that there are 4 unpaired electrons in the 3d subshell.

### Conclusion
Therefore, the number of unpaired electrons in the `Fe^(2+)` ion in the ground state is **4**.

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