## Step 1: Understanding Photon Emission and Absorption **Explanation:** - **Photon Emission** occurs when an electron moves from a higher energy level to a lower energy level. The energy difference is released as a photon. - **Photon Absorption** occurs when an electron moves from a lower energy level to a higher energy level. The electron absorbs a photon with energy equal to the difference between the levels. --- ## Step 2: Applying to Helium Ion (He⁺) Energy Levels **Explanation:** - In the context of the energy level diagram (not shown, but standard for such problems), **downward transitions** (from higher to lower energy) correspond to **photon emission**. - **Upward transitions** (from lower to higher energy) correspond to **photon absorption**. --- ## **Final Answer** - **Transitions from higher to lower energy levels correspond to photon emission.** - **Transitions from lower to higher energy levels correspond to photon absorption.** **Explanation:** When an electron falls to a lower energy state, it emits a photon (emission). When it jumps to a higher state, it absorbs a photon (absorption).

# Understanding Photon Emission and Absorption in Helium Ion (He⁺) ## Step 1: Identifying Energy Levels **Explanation:** - In an energy level diagram, each horizontal line represents a different energy state of the electron in the helium ion (He⁺). - **Higher energy levels** are located at the top, and **lower energy levels** are at the bottom. - The energy difference between these levels determines whether a photon is emitted or absorbed. --- ## Step 2: Analyzing Electron Transitions **Explanation:** - **Photon Emission:** When an electron transitions from a higher energy level to a lower energy level, it emits a photon. This is represented by arrows pointing down in the energy level diagram. - **Photon Absorption:** Conversely, when an electron transitions from a lower energy level to a higher energy level, it absorbs a photon. This is represented by arrows pointing up. --- ## Final Answer - **Photon Emission:** Occurs during transitions from higher to lower energy levels. - **Photon Absorption:** Occurs during transitions from lower to higher energy levels. **Explanation:** These transitions are fundamental in understanding how electrons interact with photons, leading to the emission or absorption of light in the helium ion.