#""^(14)"N"#, which makes up #99.6%# of a typical sample of nitrogen, and #""^(15)"N"#, which makes up #0.4%# of a typical sample of nitrogen. A synthetic isotope, #""^(13)"N"# has a half-life of #"9.965 min"#, and is therefore not stable.
https://en.wikipedia.org/wiki/Nitrogen