The ground state electronic configuration of `""_(24)Cr` is

Options

A. `[Ar]3d^(5)4s^(1)`
B. `[Ar]3d^(4)4s^(2)`
C. `[Ar]3d^(3)4s^(2)4p^(1)`
D. `[Ar]3d^(6)4s^(0)`

Explanation

To determine the ground state electronic configuration of Chromium (Cr), which has an atomic number of 24, we can follow these steps:

### Step 1: Determine the total number of electrons
The atomic number of Chromium is 24, which means it has 24 electrons in its neutral state.

### Step 2: Fill the orbitals according to the Aufbau principle
We will fill the orbitals in the order of increasing energy levels:
- 1s can hold 2 electrons
- 2s can hold 2 electrons
- 2p can hold 6 electrons
- 3s can hold 2 electrons
- 3p can hold 6 electrons
- 4s can hold 2 electrons
- 3d can hold 10 electrons

Following this order, we fill the orbitals:
- 1s² (2 electrons)
- 2s² (2 electrons)
- 2p⁶ (6 electrons)
- 3s² (2 electrons)
- 3p⁶ (6 electrons)
- 4s² (2 electrons)
- 3d⁴ (4 electrons)

At this point, we have filled a total of 24 electrons, but we need to consider the special case of Chromium.

### Step 3: Adjust for the special case of Chromium
Chromium is an exception to the expected electronic configuration due to stability preferences. To achieve a more stable half-filled d-subshell, one electron from the 4s orbital is moved to the 3d orbital.

Thus, we adjust the configuration:
- 4s¹ (1 electron)
- 3d⁵ (5 electrons)

### Step 4: Write the final electronic configuration
The ground state electronic configuration of Chromium can now be written as:
- Full configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵
- Noble gas configuration: [Ar] 4s¹ 3d⁵, where [Ar] represents the electron configuration of Argon, the nearest noble gas.

### Final Answer:
The ground state electronic configuration of Chromium (Cr) is:
**[Ar] 4s¹ 3d⁵**

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