Nitrogen is a vital element for all living things. This lesson walks through some of the properties of nitrogen, the nitrogen cycle, and other uses of nitrogen.
Nitrogen – The Element
Nitrogen is a non-metallic element found in group 15 on the periodic table.
It has an atomic number of 7, meaning it has 7 protons, and it has an atomic mass of 14.007 amu (atomic mass units).Nitrogen is usually found in a gaseous state and makes up 78% of Earth’s atmosphere. There are actually about 4,000 trillion tons of nitrogen gas in Earth’s atmosphere. Nitrogen is an inert element which means that it does not readily react with other elements.
However, nitrogen is most useful when it is mixed with other elements.Nitrogen is vital for all living things. Animals and plants both need nitrogen to make proteins. Proteins make up everything we need to live. Therefore, in a very direct and indirect way, all living things need nitrogen. However, on its own, nitrogen is usually found in an unusable gaseous form. Plants and animals are unable to obtain nitrogen while it is in gaseous form.
In order for plants and animals to obtain it, nitrogen needs to be turned into either nitrates, nitrogen compounds mixed with oxygen, or ammonium, nitrogen compounds mixed with hydrogen. The nitrogen cycle is a series of different processes that take place to make nitrates and ammonium to be used and then, at times, returned back to the cycle to be used again.Nitrogen can enter the cycle in different ways. Nitrogen fixation is one process where nitrogen enters the soil literally out of thin air.
This process uses both nitrogen-fixing organisms found in the soil to convert the nitrogen gas into usable nitrates. Lightning also brings nitrogen right to the soil. Nitrification is another process in which ammonia that is already in the soil is converted to usable nitrates by certain bacteria that live in the soil.Plants bring up the inorganic nitrates through their roots. Once inside the plant, it is mixed with other chemicals to once again create organic substances such as enzymes, proteins, and chlorophyll. Since chlorophyll is the substance that gives plants their green color, it makes sense that everything is a little greener after a lightning storm.Plants will continue to use the nitrogen until they either die or are eaten.
When a plant dies, it will decompose and return the nitrogen back into the organic form of nitrogen. When animals eat plants, they return the unused organic form of nitrogen through their waste. Since it is returned back into organic nitrogen, the process of turning it back into inorganic usable nitrogen will begin again.
Release of Nitrogen
Not all nitrogen remains directly in the system. There are many ways for the nitrogen to escape and enter the atmosphere as gas. Denitrification and volatilization are two of the main ways that nitrogen escapes the cycle. Denitrification is when the bacteria in the soil change the organic nitrogen into atmospheric nitrogen instead of the inorganic nitrates for plants to soak up. Volatilization turns urea fertilizers and manures into nitrogen gas which soon joins the atmosphere as well. Runoff is the process of losing nitrogen to our water systems. Leaching is one more process where nitrogen goes so deep into the soil so that it cannot be used.
Other Uses of Nitrogen
Nitrogen has many other uses besides just helping living things make proteins and other life sustaining substances. When large amounts of nitrogen are mixed with hydrogen, we get ammonia. Ammonia is then used to make many products such fertilizers, explosives, and nitric acid.
Let’s review. Nitrogen is a vital element needed by both plants and animals to make proteins and other life-sustaining substances. Nitrogen, in a direct and indirect way, allows for plants and animals to develop, grow, and reproduce.
Nitrogen is mainly found in a gaseous form. It actually makes up 78% of Earth’s atmosphere.The nitrogen cycle is a series of different processes that take place to make nitrates and ammonium to be used and then, at times, returned back to the cycle to be used again.
Nitrogen fixation and nitrification are two ways of bringing nitrogen into the nitrogen cycle. Denitrification, volatilization, runoff, and leaching are commons ways for nitrogen to leave the cycle. Nitrogen is also used to make items such as fertilizers and explosives.