AP Chemistryhardmcq1 pt
Bromine has two isotopes of roughly equal abundance: Br-79 and Br-81. Which peaks appear in the mass spectrum of Br₂ gas?
A.158, 160, and 162
B.79, 81, and 160
C.158 and 162 only
D.A single peak at 160
Explanation
Core Concept
Diatomic molecules can pair isotopes three ways: ⁷⁹Br–⁷⁹Br (158), ⁷⁹Br–⁸¹Br (160), and ⁸¹Br–⁸¹Br (162). Equal isotope abundance makes the 160 peak about twice as tall as each endpoint.
Correct Answer
A158, 160, and 162
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