What is the origin of first (mass of 157.836 amu) peak (of what isotopes does each consist) ? express your answers as isotopes separated by a comma?

Answer and explanation;

-Bromine molecule (Br2) consists of two bromine atoms (Br-Br). These two atoms may be originated from the same type of isotopes Br2 (11) and Br2 (22) or from two types of isotopes, Br2 (12).

The intensity of the peak depends on the abundance of the isotope. The larger the intensity of the peak, the greater the abundance of the isotope. For Br, the relative size of the peak for Br 2 molecule consisting of two different isotopes will be larger than the Br molecule consisting of same isotopes, i. e relative size of the peak for Br molecules consisting of different isotopes is twice as that of Br molecule consisting of same isotopes.

-Hence, from the data in the table we could say that the peak of mass 157.836 represents 79Br - Br peak, 159.834 represents Br - Br peak and peak of mass 161.832 represents Br - 81 81 Br

-The first peak will represent the lighter Br2 molecule, the third peak will represent the heavier Br2 molecules and the middle peak will represent the intermediate Br2 molecule which is Br2 (12).