Question

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Explanation:

Bromine has two stable isotopes, \(^{79}\text{Br}\) and \(^{81}\text{Br}\), with a relative abundance ratio close to 1:1 (or approximately 50:50, though the graph shows \(^{79}\text{Br}\) slightly more abundant, which matches bromine's isotope pattern). Selenium has multiple isotopes but not two dominant ones at 79 and 81. Gold (Au) has a much higher atomic mass (around 197) and Thallium (Tl) has isotopes like 203, 205, not in this mass range. So the mass spectrum with peaks at 79 and 81 (m/e) corresponds to Bromine.

Answer:

Bromine