Using the peak intensities provided below for the molecular ion region of an unknown, draw the corresponding mass spectrum. Be sure to label the axes and any peaks. Based on the isotopic peak intensities, suggest a composition and structure for the molecule. NOTE: You only need to consider C, H, N, O, Cl, and Br.
m/z (intensity): 136 (743), 137 (25), 138 (724), 139 (24)