When doing infrared spectroscopy an infrared light is shined on a substance to determine the vibrational frequency of the various bonds in a molecule. Because each molecule has a unique set of vibrations you can identify the molecule using this procedure, which is often used in forensics.
If you knew that part of a molecule had a high vibrational frequency, what could you say about the atoms and how they were bonded together in that part of the molecule?Another way to apply a force to a charged atom is to pass it through a magnetic field. If the field is oriented properly you will apply a force that is perpendicular to the motion of the atom, causing the atom to deflect from its previously straight line path. The amount of force depends on the charge of the atom and strength of the magnetic field.
If you had two atoms moving at the same speed with the same charge, but one atom had more mass than another, what would you expect to happen when they both enter the magnetic field?