There are many difficult concepts to comprehend in chemistry. This difficulty that many students have can come in part by the hands-off nature of learning about aspects of chemistry at the molecular level. Empowering students learning through making with a 3D printer is now accessible to all of our chemistry students through using a free, web-based program called MolView. Using MolView students can create, view and export molecules for 3D printing. In the following lessons, students learn about VSEPR Theory by modeling the various geometric structures and 3D print them.
Overview and Background
The following procedure can not only be used to teach about the VSEPR theory but within any Chemistry class where students would benefit from creating their learning and understanding of molecular concepts
Lesson Plan and Activity
Whole class work around learning about VSEPR Theory. Before students break off into their small group's students should have an understanding of the 6 basic shapes of molecular structures and the reasoning that the molecules take their shapes based upon the idea that electron pairs in the valence shell will repel and try to be as far away from each other as possible.
Create 6 break-out groups with each group assigned a different molecular structure; linear, trigonal planar, bent, tetrahedral, octahedral, trigonal pyramidal.
Have each group use MolView to create their assigned molecular structure.
The Trigonal Pyramidal molecular structure group has been tasked with creating Ammonia as it has that specific molecular structure.
Go to MolView.org and clear the edit screen. (Image 1)
Students can now create their molecular Structure. If the chemical element is not listed. Click on the … and select from the periodic table the elements that are needed. (Image 2)
Students can now create ammonia using the correct chemicals and bonding. (Image 3)
To 3D print the molecular structure you will need to download the .mol file (Image 4)
To convert the .mol file into a 3D printable file such as a .stl you will need to use Chimera. If you don’t’ have Chimera installed on your computer click on the following link and follow the onscreen guide for installation. https://www.cgl.ucsf.edu/chimera/download.html
- Click FILE and OPEN the .mol file of your saved molecule. (Image 5)
7.You can change the shape of you molecule to more accurately see the individual elements by clicking ACTIONS -> ATTOMS/BONDS -> BALL & STICK. (Image 6-7)
- The last step before you can 3D print your model is to click FILE -> EXPORT SCENE and save the model as the type 3D file that is needed. (Image 8)