Nitrogen, also called Nitrogen (N), is a chemical element with atomic number 7. It is a non-metal found in group 15 of the periodic table, and it is essential for life, as it forms a central part of amino acids and nucleic acids.
1. Introduction
Nitrogen is a colorless, odorless, and tasteless gas under standard conditions. It makes up about 78% of the Earth's atmosphere by volume. Nitrogen atoms contain 7 protons, usually 7 neutrons, and 7 electrons, giving it an average atomic mass of about 14 u.
2. Physical and Chemical Properties
Nitrogen is relatively unreactive as a diatomic gas (N₂) due to the strong triple bond between the atoms. However, it forms important compounds such as ammonia (NH₃), nitric acid (HNO₃), and various nitrates. It has a boiling point of -195.8 °C and a melting point of -210.0 °C.
3. Isotopes
Nitrogen has two naturally occurring stable isotopes:
- Nitrogen-14 (¹⁴N) – 7 protons, 7 neutrons (most common)
- Nitrogen-15 (¹⁵N) – 7 protons, 8 neutrons (used in research and tracing studies)
Nitrogen-14 is commonly used as the basis for the definition of atomic mass units in older standards.
4. Industrial Use
Nitrogen is crucial in numerous industrial and scientific fields. The table below shows the main applications:
| Use | Description |
| Ammonia production | Combined with hydrogen in the Haber process to produce ammonia for fertilizer |
| Protective atmospheres | Inert gas used in food packaging, electronics, and welding |
| Liquid nitrogen | Used for cryopreservation and cooling in scientific applications |
5. Extraction and Safety
Nitrogen is extracted by fractional distillation of liquid air. Although nitrogen gas is inert and non-toxic, it can displace oxygen in enclosed spaces, which can lead to a risk of suffocation. Liquid nitrogen must be handled with care due to its extreme cold and pressure hazards.
