Final answer:
When an electron moves to a higher energy level, it gains energy. This transition requires energy because electrons must overcome the attraction from the atomic nucleus. Electrons release energy as photons when transitioning from higher to lower energy levels, and multiple transitions with photon emission describe the fluorescence effect.
Step-by-step explanation:
When an electron moves to a higher energy level, the correct answer is c) The electron has gained energy. This process occurs because energy is needed to overcome the attraction between the negatively charged electron and the positively charged protons in the nucleus. Following the Bohr model, higher energy orbits are located further from the atomic nucleus. Electrons are attracted to the positive protons, hence, moving an electron away from the nucleus requires energy. Conversely, when an electron transitions from an excited state to a less excited state or a ground state, it will lose this absorbed energy, often by emitting a photon.
Regarding the fluorescence effect, the behavior of an electron that best represents this phenomenon is d) The electron transitions from level 8 to a lower level in multiple steps before reaching level 1. This stepwise descent results in the emission of photons at each transition, a hallmark of the fluorescence process.
In summary, an atom becomes positively ionized when an electron is lost, and during the re-capture of an electron, the atom will emit photons. Which photons are emitted will depend on whether the electron is captured directly to the lowest energy level or passes through intermediate levels. Energy levels in atoms are quantized, and emission or absorption of energy in the form of photons corresponds to transitions between these discrete energy levels.