I.

Introduction

Nitrogen, symbol N, gaseous element that makes up the largest portion of Earth's atmosphere. The atomic number of nitrogen is 7. Nitrogen is in group 15 (or Va) of the periodic table (see Periodic Law).

Nitrogen was isolated by the Scottish chemist Daniel Rutherford in 1772 and recognized as an elemental gas by the French chemist Antoine Laurent Lavoisier about 1776. The element’s name comes from the Greek nitron + genes, “nitre forming,” for nitre, a common compound of nitrogen.