Nitrogen
Nitrogen is one of the P-block nonmetal elements, after carbon and before oxygen. Nitrogen is basically a nonmetal chemical element on the Periodic Table. It's Symbol is "N" and the atomic number is 7. In a Nitrogen atom, it has 14 nucleons in the nucleus, which is 7 neutrons and protons, and has 5 electrons on the outermost shells.
History
Nitrogen was discovered by Daniel Rutherford in 1772, in which he called it noxious gas or fixed gas. It was found that many animals died in nitrogen, which was the part of the air which did not burn.
In 1910, Lord Rayleigh found out that when a spark passes through nitrogen, it makes a reactive nitrogen.
Safety
Nitrogen is not poisonous. We can breath it when it is part of the air, but we cannot breath nitrogen, or pure nitrogen, itself. If someone does, they will just fall asleep and die.