In transition elements, the differentiating electron enters into ________ subshell.

Options

A. ns
B. np
C. (n-1)d
D. (n-2)f

Answer

To solve the question about the subshell into which the differentiating electron enters in transition elements, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Transition Elements**: Transition elements are defined as those elements that have partially filled d-subshells. They are located in the d-block of the periodic table.

2. **Understand the Electron Configuration**: The electron configuration of transition metals involves filling the 4s subshell before the 3d subshell. For example, iron (Fe) has the electron configuration of [Ar] 4s² 3d⁶.

3. **Determine the Differentiating Electron**: The differentiating electron is the last electron that is added to the electron configuration of an element. In the case of transition metals, this last electron typically enters the d-subshell.

4. **Identify the Subshell**: For transition elements, the differentiating electron enters the d-subshell, which is represented as (n-1)d, where n is the principal quantum number of the outermost shell. For example, in iron, the outermost shell is 4 (4s), and the d-subshell being filled is 3 (3d).

5. **Conclude the Answer**: Therefore, the differentiating electron in transition elements enters the d-subshell.

### Final Answer:
In transition elements, the differentiating electron enters into the **d** subshell.

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