Electrons are de-exciting from the fifth orbit in hydrogen atoms but the first orbit is not availabl — Atomic Structure Chemistry Question

💡 Solution & Explanation

The available states for transition end at $n=2$. The number of possible transitions from $n=5$ to $n=2$ is given by $\frac{(n_2 - n_1)(n_2 - n_1 + 1)}{2} = \frac{(5 - 2)(5 - 2 + 1)}{2} = \frac{3 \times 4}{2} = 6$. Therefore, correct answer is B.