Final answer:
The mass spectrum of Cl2 consists of two distinct peaks corresponding to the isotopes 35Cl+ and 37Cl+ ions, which are present in a natural abundance ratio of approximately 3:1. These peaks provide information on the masses and relative abundances of the isotopes, as separated by the mass spectrometer based on their mass-to-charge ratios.
Step-by-step explanation:
Peaks in the mass spectrum of Cl2 provide information about the isotopic composition of chlorine gas. Elemental chlorine is composed of two isotopes, 35Cl and 37Cl, with a natural abundance ratio of approximately 3:1. In a mass spectrometer, chlorine molecules are ionized to Cl+ ions, and these ions are then separated according to their mass-to-charge ratios.
The mass spectrum will show two prominent peaks corresponding to the two isotopes. Since the isotopes have different masses (35 and 37 atomic mass units), they are deflected differently by the magnetic field within the mass spectrometer - lighter 35Cl+ ions are deflected more than heavier 37Cl+ ions. Measuring this deflection enables chemists to determine the masses of the ions and, by extension, their relative abundances in the sample.
The height of each peak in the mass spectrum represents the relative abundance of each ion. This means that the peak for 35Cl+ will be about three times higher than that for 37Cl+, reflecting the natural isotopic distribution of chlorine.