CHAPTER 1 Why Care About Nitrogen Every known living thing plant and animal contains nitrogen About three percent of your body is nitrogen That means if you weigh 100 pounds 45 kilograms you contain about three pounds 1 4 kg of nitrogen That’s about how much a large guinea pig weighs A nitrogen atom E N Electron Neutron Proton Tiny Building Blocks Everything in the world is made up of atoms and molecules Atoms and molecules are submicroscopic This means they are so small that they cannot be seen with an ordinary microscope Atoms are individual building blocks and molecules are combinations of those building blocks The Periodic Table of Elements lists the 118 known types of atoms For example one of those atoms is nitrogen represented on the periodic table as N P Every living thing contains nitrogen including you 4
Another is oxygen represented by the letter O When one nitrogen atom combines with two oxygen atoms they form a molecule called NO2 This is nitrogen dioxide a brown gas that is sometimes seen hanging over big cities In combination with other toxic gases this brown haze is also called smog The atoms that combine to form the most important molecules in the human body are carbon C hydrogen H phosphorus P oxygen O and nitrogen N In the center of each atom is a nucleus which contains protons and neutrons Surrounding the nucleus is a cloud of electrons The number of electrons is the same as the number of protons in an atom Nitrogen has seven protons and seven electrons Charting the Atoms The Periodic Table of Elements shows all the chemical elements known to exist Each element is made up of atoms of that type of element For example the element nitrogen consists of nitrogen atoms Some elements occur naturally and others are developed in laboratories and are therefore synthetic or human-made The periodic table lists them in order of increasing atomic number or the number of protons in the atom’s nucleus Nitrogen is number 7 in the table 5 Periodic Table of Elements
N2 N N Airborne Nitrogen Nitrogen is one of about 90 elements or pure substances that exist naturally on Earth The only place pure nitrogen is found is in the air that surrounds us About 78 percent of our air is made up of nitrogen gas or N2 That means every breath you take is mostly made of pure nitrogen The rest is oxygen with tiny bits of other gases mixed in Pure nitrogen is a tasteless colorless and odorless gas It is also called an inert gas This means that it doesn’t easily bond or join with other elements Given the opportunity a nitrogen atom will tend to bond only with another nitrogen atom The two form such a strong connection that nitrogen gas N2 does not react easily with other atoms That’s not to say it doesn’t react or bond with other atoms It just means it takes a lot of energy for that to happen Because nitrogen gas is so stable it is used in situations where chemical reactions might cause problems Potato chip bags for example are filled with nitrogen gas If the bags were filled with regular air the oxygen in that air would make the chips become stale This ordinary light bulb Ieft contains nitrogen gas which doesn’t catch fire when the metal filament or wire inside gets hot In many parts of the world these bulbs are being replaced by compact fluorescent lamps or CFLs right CFLs require far less electricity and last a lot longer than ordinary bulbs They can reduce costs save energy and help the environment by cutting down on the use of natural resources needed to produce electricity 6
N O O nitrogen dioxide NO2 1 nitrogen atom 2 oxygen atoms 3 atoms nitrous oxide N2O 2 nitrogen atoms 1 oxygen atom 3 atoms N O N N O nitric oxide or nitrogen monoxide NO 1 nitrogen atom 1 oxygen atom 2 atoms Making Sense of Cycles There are many molecules made of nitrogen and oxygen Many have the word oxide in their name and as a group they are called nitrogen oxides Oxides refers to the oxygen part of the molecule Three common ones are nitrogen dioxide NO2 nitrous oxide N2O and nitric oxide NO which is sometimes called nitrogen monoxide Here is one useful way to keep these compounds straight As you read this book keep a list of each of these three common nitrogen compounds Also list as many ways that each occurs in nature or human activity as you can find Some historical documents are preserved in airtight containers filled with nitrogen gas The United States Declaration of Independence for example is stored in this way If it were to come into contact with air the oxygen in the air would eventually destroy the document One very important place nitrogen is used is in cars Nitrogen gas is what inflates the airbags and protects you in a car when it crashes Because nitrogen is so stable it won’t react with other elements and cause an explosion in case there’s a fire 7 If crash test dummies could talk they would sing the praises of airbags inflated with nitrogen gas Not only do the bags protect us from impact injuries but the nitrogen is so stable that it reduces the chance of explosions and fire
