After studying Chapter 13 Mass Spectrometry and Infrared Spectroscopy, my muddiest point is section 13.2 Alkyl Halides and the M + 2 Peak on pg. 467. I don’t understand the ratio concepts. For example, 35Cl and 37Cl occur at a 3:1 ratio. The text states that if it is a 3:1 ratio, there will be a Cl in the atom. How are we supposed to determine the ratio or is it generally given information? Also, it states that the bromine is a 1:1 ratio. Why is it different from the Cl, which is 3:1? Also, understanding the M + 2 Peak is very confusing. I understand that it is the mass of the compound + 2, but what is the significance? After further reading of the text, the M + 2 peak is used for alkyl halides that have a mass slightly higher than their mass on the periodic table. With further reading, I learned that with an M + 2 peak, there will be two peaks towards the end of a graph showing the presence of the alkyl halide. Based on the text, chlorine and bromine have two isotopes and carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, fluorine, and iodine only have one major isotope. After reviewing the sample problem for determining molecular ions in a mass spectrum of a particular compound, I feel like I understand the concept better.
