Statement-I : No two electrons in an atom can have the same values of four quantum number.
Because
Statement-II : No two electrons in an atom can be simultaneously in the same shell, same subshell, same orbitals and have same spin.

Options

A. Statement-I is true, Statement-II is true , Statement-II is correct explanation for Statement-I.
B. Statement-I is true, Statement-II is true , Statement-II is NOT a correct explanation for statement-I
C. Statement-I is true, Statement-II is false
D. Statement-I is false, Statement-II is true

Answer

To solve the question, we need to analyze both statements provided and determine their validity based on the principles of quantum mechanics, specifically the Pauli Exclusion Principle.

### Step-by-Step Solution:

1. **Understanding Quantum Numbers**:
- Electrons in an atom are described by four quantum numbers:
- Principal quantum number (n)
- Azimuthal quantum number (l)
- Magnetic quantum number (m_l)
- Spin quantum number (m_s)

2. **Pauli Exclusion Principle**:
- According to the Pauli Exclusion Principle, no two electrons in an atom can have the same set of four quantum numbers. This means that every electron must differ in at least one of these quantum numbers.

3. **Analyzing Statement-I**:
- Statement-I claims that "No two electrons in an atom can have the same values of four quantum numbers."
- This statement is true because it directly reflects the Pauli Exclusion Principle.

4. **Analyzing Statement-II**:
- Statement-II states that "No two electrons in an atom can be simultaneously in the same shell, same subshell, same orbitals and have the same spin."
- This statement is also true. If two electrons were to occupy the same orbital (same n, l, and m_l) and have the same spin (same m_s), they would have identical quantum numbers, which contradicts the Pauli Exclusion Principle.

5. **Conclusion**:
- Both statements are correct. Therefore, the answer to the question is that both Statement-I and Statement-II are true.

### Final Answer:
Both Statement-I and Statement-II are true.

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