1. The problem statement, all variables and given/known data N2 molecules absorb ultraviolet light, but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of the following statements explains the observations? a) More energy is required to make N2 molecules vibrate than is required to make I2 molecs. vibrate b) More energy is required to remove an electron from an I2 molecule than is required to remove an electron from a N2 molecule. c) visible light does not produce transitions between electronic energy levels in the N2 molecule but does produce transitions in the I2 molecule. d) the molecular mass of I2 is greater than the molecular mass of N2. In my AP Chem class, we did not cover the absorption of light by molecules, but I found this problem above in the course description on the collegeboard site. Could anyone explain why C is right and the other answers are wrong [and direct me at the theory needed to solve]? 2. Relevant equations no equations 3. The attempt at a solution I thought that since UV light has more energy than visible light and N2 can absorb only energy from UV light, then the energy from the visible light is inadequate for exciting it. I2 molecules absorb both visible and uv light successfully, so they require less energy to excite. I know... this is a half-baked guess. Anyways, I am looking forward to hearing your inputs. Thanks in advance and for the time.