<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Skip Navigation

Bohr Model of the Atom

Also known as the planetary model, electrons are organized into energy levels with the nucleus at the center.

Atoms Practice
Estimated1 minsto complete
Practice Bohr Model of the Atom
This indicates how strong in your memory this concept is
Estimated1 minsto complete
Practice Now
Turn In
Scanning Tunneling Microscopy

Scanning Tunneling Microscopy

Credit: Taner Yildirim (The National Institute of Standards and Technology - NIST)
Source: http://en.wikipedia.org/wiki/File:Chiraltube.gif
License: CC BY-NC 3.0

A scanning tunneling microscope (STM) is used to view surfaces at the atomic level. Currently, scanning tunneling microscopy is being used to investigate the properties of carbon nanotubes, such as the one pictured above.

Amazing But True

  • One of the methods currently available to scientists to image individual atoms employs the use of a scanning tunneling microscope. An STM works by the principle of quantum tunneling. To understand quantum tunneling, you must first understand how electrons classically behave in metals. Classically, the loosest electrons in metals are held in the metal unless given enough energy to leave the metal atom. 
  • However, when looked at through the principles of quantum mechanics, the most loosely bound electrons in a metal can "tunnel" through the energy barrier. This requires less energy than would be necessary for the electrons to get over the energy barrier and actually leave the metal atom. 
  • By using a very small electrically charged probe, the electrical current on the surface of a metal can be monitored. From this data, the location of atoms on the surface of a metal can be plotted. This is the basis of how a scanning tunneling microscope can image individual atoms.  
  • Credit: O. Usher (UCL MAPS)
    Source: http://www.flickr.com/photos/uclmaps/11796325765/
    License: CC BY-NC 3.0

    Scanning Tunneling Microscopes attain images of metal surfaces at the atomic level [Figure2]


Explore More

Using the information provided above, answer the following questions.

  1. Why don't we see objects tunnel through walls in our everyday life?
  2. Why can't someone use a regular microscope to view atoms?

Notes/Highlights Having trouble? Report an issue.

Color Highlighted Text Notes
Please to create your own Highlights / Notes
Show More

Image Attributions

  1. [1]^ Credit: Taner Yildirim (The National Institute of Standards and Technology - NIST); Source: http://en.wikipedia.org/wiki/File:Chiraltube.gif; License: CC BY-NC 3.0
  2. [2]^ Credit: O. Usher (UCL MAPS); Source: http://www.flickr.com/photos/uclmaps/11796325765/; License: CC BY-NC 3.0

Explore More

Sign in to explore more, including practice questions and solutions for Bohr Model of the Atom.
Please wait...
Please wait...