Halogenated compounds are particularly easy to identify by their mass spectra because chlorine and bromine occur naturally as mixtures of two abundant isotopes. . Chlorine occurs as Cl (75.8%) and Cl (24.2%); . Bromine occurs as "Br (50.7%) and 81 Br (49.3%); For the compound bromoethane, C2 HBr: At what masses do the molecular ions occur? (List in order of increasing mass separated by commas with no space, e.g. 120,122.) 94,96 X What are the percentages of each molecular ion? (List to nearest 1% in order of increasing mass separated by commas, e.g. 55,45.) 51,49 MacBook Pro