N2 molecules absorb ultraviolet light but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of th
e following statements explains the observations? More energy is required to make N2 molecules vibrate than is required to make I2 molecules vibrate.
A
More energy is required to remove an electron from an I2 molecule than is required to remove an electron from a N2 molecule.
B
Visible light does not produce transitions between electronic energy levels in the N2 molecule but does produce transitions in the I2 molecule.
C
The molecular mass of I2 is greater than the molecular mass of N2.
C. Visible light does not produce transitions between electronic energy levels in the N₂ molecule but does produce transitions in the I₂ molecule.
Explanation:
Abortion of light by molecules will produce electronic transitions from a ground level to a higher level equal to the energy of absorbed light.
In the case of nitrogen (N₂) the allowed electronic transitions are between electronic energy levels with a energy difference equal to the energy of photons of the ultraviolet light. Nitrogen will not absorb from the visible range so it is colorless.
Now iodine (I₂) have the allowed electronic transitions between electronic energy levels with a energy difference equal to the energy of photons of the visible light. As a consequence Iodine vapors have a violet color.
