Most abundant gas in the atmosphere. It makes up a little more than 3/4 of the air we breathe. Each nitrogen molecule consists of two nitrogen atoms.
Even though oxygen is the second most abundant gas in the atmosphere, it makes up less than one fourth of the value. Plants and animals take oxygen directly from the air and use it to release energy from their food. Has two oxygen atoms
a form of oxygen that has three oxygen atoms in each molecule instead of two.
Each molecule of this has one atom of carbon and two atoms of oxygen. Essential to life. Plants must have carbon dioxide to produce food. When the cells of plants and animals break down food to produce energy, they give off this as a waste product. When fuels such as coal and gasoline are burned they release it. Burning these fuels increases the amount of this in the atmosphere
water in the form of gas. It is invisible. It is not the same thing as steam, each water molecule contains two atoms of hydrogen and one atom of oxygen. clouds form when this condenses out of the air to form tiny droplets of liquid water or crystals of ice. If they become heavy enough, they can fall as rain or snow.