Final answer:
The frequency of the stretching vibration of a bond in IR spectroscopy depends on the masses of the atoms and the stiffness of the bond. These factors are analogous to the mass of balls and the stiffness of springs in a physical model, with heavier atoms and stiffer bonds affecting the vibrations' natural frequencies.
Step-by-step explanation:
The frequency of the stretching vibration of a bond in IR spectroscopy depends on two primary quantities: the masses of the atoms involved in the bond and the stiffness of the bond, which can also be referred to as force constant. These two factors influence the natural vibrational frequencies of the chemical bonds within a molecule. As such, the correct answer to the question is option (c).
The concept is analogous to balls and springs, where atoms are seen as "balls" and bonds act like "springs". A bond between lighter atoms will vibrate at a higher frequency compared to a bond between heavier atoms, all else being equal. Similarly, a stiffer bond, which can be thought of as a stronger or more tightly held bond, will have a higher vibrational frequency than a less stiff bond.
It is important to note that while electronegativity and nuclear charges can affect the polarity and strength of bonds, they are not the direct factors affecting the vibrational frequencies measured in IR spectroscopy.