Question

1. the mass spectrum for elemental bromine is represented below. label each peak with the appropriate nuclide (isotope) symbols. note: not all elements exist as single atoms in nature.

Explanation:

Step1: Recall bromine isotopes

Bromine has two stable isotopes, $^{79}$Br and $^{81}$Br.

Step2: Consider bromine molecule

Bromine exists as $Br_2$ in nature. The possible combinations for $Br_2$ are $^{79}$Br$^{79}$Br (m/z = 158), $^{79}$Br$^{81}$Br (m/z = 160), and $^{81}$Br$^{81}$Br (m/z = 162). The lower - intensity peaks around m/z = 80 are likely due to $Br^+$ ions from dissociation of $Br_2$ during mass - spectrometry process.

Step3: Label the peaks

The peaks around m/z = 80 are $^{79}$Br$^+$ and $^{81}$Br$^+$. The peaks around m/z = 158, 160, 162 are $^{79}$Br$^{79}$Br, $^{79}$Br$^{81}$Br, $^{81}$Br$^{81}$Br respectively.

Answer:

The peaks around m/z = 80: $^{79}$Br$^+$, $^{81}$Br$^+$; The peaks around m/z = 158: $^{79}$Br$^{79}$Br; The peak around m/z = 160: $^{79}$Br$^{81}$Br; The peak around m/z = 162: $^{81}$Br$^{81}$Br