In manganese atom , `Mn (Z = 25)`, the total number of orbitals populated by one or more electrons (in ground state) is :

Options

A. 15
B. 14
C. 12
D. 10

Explanation

To determine the total number of orbitals populated by one or more electrons in a manganese atom (Mn, Z = 25), we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number**:
The atomic number of manganese (Mn) is 25. This means that a neutral manganese atom has 25 electrons.

2. **Write the Electron Configuration**:
The electron configuration for manganese can be written as follows:
- 1s²
- 2s²
- 2p⁶
- 3s²
- 3p⁶
- 4s²
- 3d⁵

So, the complete electron configuration is:
\[ \text{Mn: } 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^5 \]

3. **Count the Number of Orbitals**:
Now, we will count the number of orbitals that are populated by one or more electrons:
- **1s**: 1 orbital
- **2s**: 1 orbital
- **2p**: 3 orbitals (2p has three orientations: px, py, pz)
- **3s**: 1 orbital
- **3p**: 3 orbitals
- **4s**: 1 orbital
- **3d**: 5 orbitals

Now, let's sum these up:
\[ 1 (1s) + 1 (2s) + 3 (2p) + 1 (3s) + 3 (3p) + 1 (4s) + 5 (3d) = 15 \text{ orbitals} \]

4. **Conclusion**:
Therefore, the total number of orbitals populated by one or more electrons in the ground state of manganese is **15**.

### Final Answer:
The total number of orbitals populated by one or more electrons in manganese (Mn, Z = 25) is **15**.

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