Copyright

What is Oxygen? - Formula & Levels

What is Oxygen? - Formula & Levels
Coming up next: What is Silica? - Properties & Definition

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:03 Background on Oxygen
  • 1:20 Oxygen's Structure and…
  • 5:11 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Timeline
Autoplay
Autoplay
Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Gail Marsella
Breathe! You've just processed another dose of oxygen. Learn about some different forms of oxygen critical to life on Earth, particularly dioxygen and ozone.

Background on Oxygen

Oxygen makes up about 21% of the atmosphere. It's a very reactive chemical element and can combine with almost anything to make various compounds. Fire, for example, so useful for heat and light yet so damaging to wood structures, is a vigorous reaction of oxygen with burnable materials like wood or other fuels. Many metals react with oxygen to form oxides. Of particular commercial interest is the collection of iron oxides known as rust. A billion dollar problem around the world, rust weakens bridges and buildings, damages engines and tools, and corrodes pipes.

Yet oxygen is also essential for living things. Oxygen releases energy from nutrients in every living cell, a process called cellular respiration. One type of oxygen, ozone, protects us from the most damaging ultraviolet light in sunlight. You might be wondering why such a reactive element is still present in the atmosphere in such large quantities after all this time. The answer is photosynthesis, carried out by all green plants. Oxygen is a waste product of photosynthesis, which fuses water and carbon dioxide into sugars, so you can think of your local park or forest as a place where oxygen is pumped back into the environment.

Oxygen's Structures and Properties

Oxygen is a chemical element, with the symbol O. Several allotropes, or molecular forms, of it exist, but the three most common in our environment are molecular oxygen, or dioxygen, O2; ozone, O3; and to a much lesser extent, atomic oxygen, O. A solid allotrope of oxygen exists in several colors, but only under extremes of low temperature and high pressure.

Atomic oxygen is very rare except at the uppermost regions of the atmosphere, where the air is extremely thin and the intense sunlight energy can split dioxygen into individual atoms. In the lower atmosphere, atomic oxygen reacts almost immediately with other atoms to form compounds. Each oxygen atom has eight protons in the nucleus and eight electrons outside the nucleus. Chemists think of electrons as forming a cloud around the nucleus, stacked up in levels or shells. The outer shell of the oxygen atom only has six electrons, and these are the ones most likely to participate in chemical reactions. An outer shell is generally most stable if it has eight electrons, also called an octet.

Dioxygen, most often just called oxygen, is the most common form of elemental oxygen and the one you're metabolizing right now as you breathe. It's colorless, odorless, and tasteless, although when liquefied at low temperature it becomes a lovely pale blue. A stream of liquid dioxygen is attracted by an external magnetic field, so it's classified as paramagnetic. Diamagnetic materials are weakly repelled by a magnetic field. It boils around -183 degrees C, which -297 degrees F, and freezes at -218 degrees C, or -361 degrees F, so in our environment it's virtually always a gas.

Dioxygen has two oxygen atoms bonded with a double bond. This allows both oxygen atoms to have an octet of electrons in their outer shells because two pairs of electrons are shared between the two atoms. This stability means dioxygen is not as reactive as atomic oxygen, but it's good enough to feed fires, particularly in hot, dry conditions; create rust, particularly in wet, salty conditions; and run the energy-releasing parts of your biochemistry. Enough dioxygen dissolves in water to support fish and other water creatures. In human blood, dioxygen is delivered to cells by the hemoglobin molecule in red blood cells.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support