Nitrogen (symbol N, atomic number 7) is the gas that makes up 78% of Earth's atmosphere and a key building block of proteins and fertiliser. It is classified as a reactive nonmetal and sits in group 15, period 2 of the periodic table.
Overview
Nitrogen is the chemical element with atomic number 7 and the symbol N. With a standard atomic weight of 14.007, it is a reactive nonmetal. In the periodic table it occupies group 15 and period 2, and under standard conditions it is normally a gas. Nitrogen is the gas that makes up 78% of Earth's atmosphere and a key building block of proteins and fertiliser.
Atomic structure
An atom of Nitrogen has 7 protons in its nucleus and, when neutral, 7 electrons arranged in the configuration [He] 2s2 2p3. Its standard atomic weight of 14.007 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Nitrogen was discovered in 1772 by Daniel Rutherford. It follows Carbon (C) and precedes Oxygen (O) in order of atomic number.
| Atomic number | 7 |
|---|---|
| Symbol | N |
| Atomic mass | 14.007 |
| Category | Reactive nonmetal |
| Group | 15 |
| Period | 2 |
| Electron configuration | [He] 2s2 2p3 |
| Phase at STP | Gas |
| Discovered | 1772 (Daniel Rutherford) |