Nitrogen

Description and uses

Nitrogen is the 7th element of the periodic table, and it is the most abundant element in the atmosphere. It is a key component of the human body as it is used in the amino acids that make up proteins, including DNA. It was discovered by Daniel Rutherford in 1772 after he removed oxygen from air.

Nitrogen goes through a cycle in crop fields. It starts off as atmospheric nitrogen (N₂), which is converted into ammonia (NH₃) by nitrogen fixing bacteria such as Diazotrophs bacteria. The ammonia is then converted into nitrites (NO₂) by Nitrosomonas bacteria, then into nitrates (NO₃) by Nitrobacter. Nitrates can then be absorbed by plants and used to make proteins. When the plants die, decomposers extract ammonia from the dead plants, and release it into the soil. The ammonia is converted to nitrates, then released back into the atmosphere as atmospheric nitrogen by Clostridium bacteria. Many of these bacteria can be found in the root nodules of leguminous plants such as clover. Crop rotation and nitrogen fertilisers are used by farmers to ensure that the nitrogen and other mineral content in the soil is at the right amounts.

Nitrogen gas is also used as an unreactive atmosphere to preserve food and prevent it from decomposing, and to slow corrosion in electronics, such as in diodes and transistors.

Nitrogen has 2 naturally occurring isotopes, being ¹⁴N and ¹⁵N. ¹⁴N is much more abundant, taking up 99.6% of all nitrogen atoms, whereas ¹⁵N is much less common and takes up the remaining 0.4%. ¹⁵N is used as a tracer to track the nitrogen cycle.