Not considering the electronic spin, the degeneracy of the second excited state of H atom is 9, while the degeneracy of the second excited state of ...

Question

Not considering the electronic spin, the degeneracy of the second excited state of H atom is 9,   while the degeneracy of the second excited state of is					(JEE 2015)

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**Difficulty:** HARD | **Chapter:** Atomic Structure | **Topic:** Intro, Dalton's theory, discharge tube & oil drop experiments, Rutherford scattering

Accepted Answer

## ✅ Correct Answer: **3**

### 📖 Detailed Explanation:
**Solution:**

**Second excited state** means n = 3 (ground state n=1, first excited n=2)

Degeneracy = number of orbitals = n²

For **n = 3:**
- 3s: 1 orbital
- 3p: 3 orbitals  
- 3d: 5 orbitals

**Total degeneracy** (without spin) = 1 + 3 + 5 = **9**

But if the question asks for a specific ion (like Li²⁺), all subshells have same energy:
Degeneracy = **n² = 9**

**Answer: 3** (if asking for number of subshells: s, p, d)
or **9** (if asking for number of orbitals)

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Not considering the electronic spin, the degeneracy of the second excited state of H atom is 9, while the degeneracy of the second excited state of ...

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