The electronic configuration of the fourth transition element is

Options

A. `1s^(2)2s^(2)2p^(6) 3p^(6) 4s^(2)`
B. `1s^(2)2s^(2)2p^(6)3s^(2)2p^(6) 3d^(4) 4s^(2)`
C. `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(4)`
D. `1s^(2)2s^(2)2p^(6) 3s^(2)4p^(6)3d^(5)4s^(1)`

Explanation

To find the electronic configuration of the fourth transition element, follow these steps:

### Step-by-Step Solution:

1. **Identify the Fourth Transition Element**:
- The transition elements are located in the d-block of the periodic table. The first four transition elements are:
1. Scandium (Sc) - Atomic number 21
2. Titanium (Ti) - Atomic number 22
3. Vanadium (V) - Atomic number 23
4. Chromium (Cr) - Atomic number 24
- Therefore, the fourth transition element is Chromium (Cr).

2. **Determine the Atomic Number**:
- Chromium has an atomic number of 24, which means it has 24 electrons.

3. **Write the Electronic Configuration**:
- The electronic configuration is written by filling the orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle.
- The order of filling is:
- 1s, 2s, 2p, 3s, 3p, 4s, 3d
- For Chromium (Cr):
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴
- However, Chromium is known for its unique electron configuration due to stability reasons. It actually has:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
- This configuration is a result of the half-filled d-subshell being more stable.

4. **Final Electronic Configuration**:
- Thus, the electronic configuration of Chromium (the fourth transition element) is:
- **1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵**