Mass spectroscopy

carbon isotopes

¹²C- 99%

¹³C- 1.1%

Bromine Isotopes

2 isotopes of equal abudance ⁷⁹B- 50%, ⁸¹B- 50%. 1:1 ratio of M+ and M+2.

Chlorine Isotopes

2 isotopes in different abundances, ³⁵C- 75%, ³⁷C- 25%. Also observed as 3:1 ratio of M+ and M+2.

Nitrogen Rule no nitrogen atoms

zero

Nitrogen rule one nitrogen atom

odd

Nitrogen rule two nitrogen atoms

even