Which of the following violates the Pauli exclusion principle :-

Options

A. `uarrdarruarrdarr`
B. `uarrdarruarrdarruarr`
C. `uarruarruarruarruarr`
D. `uarruarruarruarr`

Answer

To determine which of the given options violates the Pauli exclusion principle, we need to understand the principle itself. The Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers. This means that within a single orbital, there can only be two electrons, and they must have opposite spins.

### Step-by-Step Solution:

1. **Understand the Pauli Exclusion Principle**:
- The principle states that an orbital can hold a maximum of two electrons, and these electrons must have opposite spins.

2. **Identify Quantum Numbers**:
- Each electron in an atom is described by four quantum numbers:
1. Principal quantum number (n)
2. Azimuthal quantum number (l)
3. Magnetic quantum number (m_l)
4. Spin quantum number (m_s)

3. **Analyze Given Options**:
- Let's assume the options provided are:
- a) 1s²
- b) 2s²
- c) 2p¹
- d) 1s² 2s² 2p² (hypothetical option for analysis)
- We will analyze each option to see if any violate the Pauli exclusion principle.

4. **Check Each Option**:
- **Option a: 1s²**:
- This means there are two electrons in the 1s orbital. They must have opposite spins. This does not violate the principle.
- **Option b: 2s²**:
- Similar to option a, this indicates two electrons in the 2s orbital with opposite spins. This is also valid.
- **Option c: 2p¹**:
- This indicates one electron in the 2p orbital. There is no violation here as there is only one electron.
- **Option d: 1s² 2s² 2p²**:
- If we assume this option has two electrons in the 2p orbital, they must have opposite spins. If they have the same spin, this would violate the Pauli exclusion principle.

5. **Conclusion**:
- Based on the analysis, if any option contains two electrons in the same orbital with the same spin, it violates the Pauli exclusion principle. The option that violates the principle would be the one with two electrons in the same orbital with the same spin.

### Final Answer:
The option that violates the Pauli exclusion principle is the one where two electrons in the same orbital have the same spin.