Electronic configuration of multielectron atoms can be written by the use of four quantum numbers and also by following certain principles. Pauli's exclusion principle suggests that maximum capacity of an atomic orbital is two. Auf bau principle suggests that the lower energy orbitals are filled first and hence stability can be attained. Hunds rule of maximum multiplicity suggests that pairing occurs with one electron. The arrangement of electrons in the space around the nucleus can be understood only after writing the electronic configuration. Thus writing electronic configuration is more important in the structure of an atom. Five unpaired electrons are present in the ground state electronic configuration of the element

Options

A. Carbon
B. Oxygen
C. Manganese
D. Chromium

Answer

To determine which element has five unpaired electrons in its ground state electronic configuration, we will analyze the electronic configurations of carbon (C), oxygen (O), manganese (Mn), and chromium (Cr).

### Step 1: Write the electronic configurations of each element.

1. **Carbon (C)**: Atomic number = 6
- Electronic configuration: \(1s^2 2s^2 2p^2\)

2. **Oxygen (O)**: Atomic number = 8
- Electronic configuration: \(1s^2 2s^2 2p^4\)

3. **Manganese (Mn)**: Atomic number = 25
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5\)

4. **Chromium (Cr)**: Atomic number = 24
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^4\) (but it is known that one electron from 4s shifts to 3d, resulting in \(4s^1 3d^5\))

### Step 2: Analyze the number of unpaired electrons.

1. **Carbon (C)**:
- Configuration: \(1s^2 2s^2 2p^2\)
- In the 2p subshell, there are 2 electrons in 3 orbitals:
- 2p: ↑↑__ (2 unpaired electrons)

2. **Oxygen (O)**:
- Configuration: \(1s^2 2s^2 2p^4\)
- In the 2p subshell, there are 4 electrons in 3 orbitals:
- 2p: ↑↑__ (2 unpaired electrons)

3. **Manganese (Mn)**:
- Configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5\)
- In the 3d subshell, there are 5 electrons in 5 orbitals:
- 3d: ↑↑↑↑↑ (5 unpaired electrons)

4. **Chromium (Cr)**:
- Configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5\) (after electron shift: \(4s^1 3d^5\))
- In the 3d subshell, there are 5 electrons in 5 orbitals:
- 3d: ↑↑↑↑↑ (5 unpaired electrons), but in the 4s subshell, there is 1 electron:
- 4s: ↑ (1 unpaired electron)
- Total unpaired electrons: 6 (5 from 3d and 1 from 4s)

### Step 3: Conclusion
From the analysis, manganese (Mn) has 5 unpaired electrons in its ground state electronic configuration.

### Final Answer:
The element with five unpaired electrons in its ground state electronic configuration is **Manganese (Mn)**.

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