What is an Energy Level of an Atom? - Definition & Equation

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What is Argon? - Facts, Properties & Uses

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 The Bohr Atomic Model:…
  • 1:46 Emission of Light and…
  • 3:17 Emission Spectra of…
  • 3:58 Lesson Summary
Add to Add to Add to

Want to watch this again later?

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

Login or Sign up

Timeline
Autoplay
Autoplay

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Alfonso Reina
In this lesson, you will learn about the possible energy states that an electron can have in an atom. You will also understand how these energy levels give rise to the light emission spectra of individual atoms.

The Bohr Atomic Model: Electron Energy Levels

At the beginning of this century, it was already known that atoms were made of protons at the center (the nucleus) and electrons orbiting around them. Scientists later realized that the light emitted from a particular type of atom occurred at specific frequencies. That is, the light given off by a collection of atoms in the gas phase could only be of certain colors. To explain this observation, Niels Bohr proposed that electrons inside an atom occupy only certain allowed orbitals with a specific energy. In other words, the energy of an electron in an atom is not continuous, but 'quantized.' The energies corresponding to each of the allowed orbitals are called energy levels.

To understand this better, think about a bookshelf. Each shelf contains books just like how each possible orbital in an atom contains electrons. Each shelf is different from the others just like how each orbital represents different energy levels for electrons. An electron can't have an energy value half way between two energy levels in an atom. Similarly, a book cannot be placed half way between consecutive shelves. It can only be placed within one shelf.

Each energy level is labeled with the quantum number n (n=1, 2, 3,...) and the energy of a particular level can be determined by the following:

En=-Rh (1/n^2)

This is where Rh is the Rydberg constant of the element. For the simplest atom, the hydrogen atom, Rh=2.18*10^-18 J.

Emission of Light and Transitions Between Energy Levels

The electrons of individual atoms can be excited from a lower energy state to a higher energy state as shown in the image below. This happens, for example, when a high voltage is applied through a collection of atoms in the gas phase. However, electrons tend to avoid excited states, so after a short time they transition to a lower energy state called relaxation. Because energy was absorbed to excite the electron, energy has to be emitted after the electron transitions to its initial state. The energy is then released in the form of light (electromagnetic waves). The energy difference between the two energy levels involved in the transition defines the color of the light emitted from the atoms. Each color of light has a particular energy and frequency.

High voltage applied to a gas tube containing individual atoms. Electrons in the atoms are excited to higher energy levels. When electrons relax to lower energy levels light is emitted.

The energy of the light emitted from a particular transition can be calculated in the following way:

emission energy

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

Register for a free trial

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
Free 5-day trial

Earning College Credit

Did you know… We have over 160 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 free for 5 days!
Create an account
Support