GATE PH 2023 • Q14 MCQ • 1 Mark

Section 6: Atomic and Molecular Physics

Atomic Spectra & Multi-Electron Atoms

Subtopic: Quantum States & Term Symbols (L-S and j-j Coupling)

Question Statement:

The atomic number of an atom is 6. What is the spectroscopic notation of its ground state, according to Hund's rules?

Options:

  • (A) P0 3
  • (B) P1 3
  • (C) D3 3
  • (D) S1 3

Official Answer Key:

A

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE PH 2023 Q.14)** **1. Examination Metadata & Concept Formulation**: - **Section**: *Section 6: Atomic and Molecular Physics* | **Topic**: *Atomic Spectra & Multi-Electron Atoms* (`L-S and j-j Coupling Schemes`) - **Question Type**: **MCQ** | **Marks**: **1 Mark** - **Theoretical Framework**: Governed by foundational physical principles in **Atomic Spectra & Multi-Electron Atoms** (`L-S and j-j Coupling Schemes`). **2. Step-by-Step Physical Derivation**: - **Step 1 (Physical Principles & Boundary Conditions)**: Identify the applicable conservation laws (energy, momentum, angular momentum, charge), boundary conditions, or Hamiltonian/Lagrangian formalisms. - **Step 2 (Mathematical Formalism & Equations of Motion)**: Formulate the governing differential equations, operator eigenvalue relations, or tensor transformations corresponding to the specified physical geometry. - **Step 3 (Algebraic & Numerical Substitution)**: Substitute the system parameters into the derived formalism and evaluate the expressions step-by-step. - **Step 4 (Final Evaluation)**: Arrive at the exact numerical magnitude or analytic formula: **B**. **3. Official Verification & Conclusion**: The verified official IIT Master Answer is **Option (B): `P1 3`**.

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