American Chemical Society (ACS) Chemistry Test 2025 – 400 Free Practice Questions to Pass the Exam

The transition that results in the greatest emission of energy occurs when an electron moves from a higher energy level to a lower energy level. In the context of the hydrogen atom or other hydrogen-like systems, energy levels are quantized and become less separated as the principal quantum number increases.

In the case of the transition from \( n=2 \) to \( n=1 \), the electron is moving from a higher energy state (n=2) to the lowest energy state (n=1), making this transition correspond to the emission of the most energy. The energy emitted during this transition can be calculated using the Rydberg equation for hydrogen, which shows that the energy difference between these two levels will be greater compared to transitions involving higher levels, such as \( n=3 \) to \( n=2 \) or \( n=2 \) to \( n=3 \), both of which involve smaller differences in energy levels.

In conclusion, the transition from \( n=2 \) to \( n=1 \) results in the greatest emission of energy because it involves the largest energy difference between the quantized states, releasing higher energy photons in the process.