The presence of Br atom produces 2 ions (M and M+2) with the same abundance.
Explanation:
Mass spectrometry is an instrumental technique in which chemical substances are ionized and fragmented. The nature of the substances produce different fragmentations.
A way to know if a substance contains bromine is seeing the parent molecular ion (M, Subtance with ⁷⁹Br) and M+2 (Substance with ⁸¹Br) with the same relative abundance. Where parent molecular ion is the substance without fragmentations
<em>That is because in nature, the isotope abundance of bromine is ⁷⁹Br with 51% and ⁸¹Br with 49%, producing the 49% of ions having 2 units of m/z higher than its consecutive ion.</em>
The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.