Definition:Nitrogen
Chemical Element
Nitrogen is the chemical element that has $7$ protons in the nuclei of its atoms.
Its chemical symbol is $\text N$.
Isotopes
N-$14$
Nitrogen-$14$ is the isotope of nitrogen which has $7$ neutrons in addition to its $7$ protons.
N-$14$ is the more common of the two stable isotopes of nitrogen, making up $99.634 \%$ of the nitrogen found on Earth.
N-$15$
Nitrogen-$15$ is the isotope of nitrogen which has $8$ neutrons in addition to its $7$ protons.
N-$15$ is the less common of the two stable isotopes of nitrogen, making up $0.366 \%$ of the nitrogen found on Earth.
Linguistic Note
The word nitrogen derives from the name niter (British English: nitre), the classical name for saltpeter (British English: saltpetre).
The word nitre in its turn descends from the ancient Greek νιτρων (nitron), itself a descendant from ancient Egyptian netjeri