Why is there so much nitrogen in the atmosphere

Formation processes in the atmosphere are related to its chemical composition, which in turn influenced the climate processes. 4.56 billion years ago, when the globe was formed, hydrogen (H2), helium (He) and nitrogen (N) were already present. Resulted in intense ultraviolet radiation photochemical decomposition of molecules of water, methane and ammonia, thereby accumulating carbon dioxide and nitrogen. Lighter gases such as hydrogen and helium, climbed up into the atmosphere, after that releasing into outer space, while the heavier gases such as carbon dioxide dissolved in the oceans largely. Nitrogen, chemically inert under the existent conditions then, it remained unchanged in atmosphere, still being after about 3.4 billion years the most important component of the atmosphere.

Nitrogen makes up 78% of the air.

Scientists believe that most of the nitrogen in the air was carried out underwater volcanoes.

The nitrogen molecule is heavier than most other molecules in the atmosphere, so it tends to settle towards the bottom.